<?xml version="1.0" encoding="UTF-8"?>
<crossref_result xmlns="http://www.crossref.org/qrschema/3.0" version="3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.crossref.org/qrschema/3.0 http://www.crossref.org/schemas/crossref_query_output3.0.xsd">
  <query_result>
    <head>
      <doi_batch_id>none</doi_batch_id>
    </head>
    <body>
      <query status="resolved">
        <doi type="journal_article">10.1190/geo2020-0411.1</doi>
        <crm-item name="publisher-name" type="string">Society of Exploration Geophysicists</crm-item>
        <crm-item name="prefix-name" type="string">Society of Exploration Geophysicists</crm-item>
        <crm-item name="member-id" type="number">186</crm-item>
        <crm-item name="citation-id" type="number">122695443</crm-item>
        <crm-item name="journal-id" type="number">5981</crm-item>
        <crm-item name="deposit-timestamp" type="number">2026041612394669400</crm-item>
        <crm-item name="owner-prefix" type="string">10.1190</crm-item>
        <crm-item name="last-update" type="date">2026-04-16T16:39:58Z</crm-item>
        <crm-item name="created" type="date">2020-12-24T12:11:12Z</crm-item>
        <crm-item name="citedby-count" type="number">21</crm-item>
        <doi_record>
          <crossref xmlns="http://www.crossref.org/xschema/1.1" xsi:schemaLocation="http://www.crossref.org/xschema/1.1 http://doi.crossref.org/schemas/unixref1.1.xsd">
            <journal>
              <journal_metadata language="en">
                <full_title>Geophysics</full_title>
                <issn media_type="print">0016-8033</issn>
                <issn media_type="electronic">1942-2156</issn>
              </journal_metadata>
              <journal_issue>
                <publication_date media_type="print">
                  <month>03</month>
                  <day>01</day>
                  <year>2021</year>
                </publication_date>
                <journal_volume>
                  <volume>86</volume>
                </journal_volume>
                <issue>2</issue>
              </journal_issue>
              <journal_article publication_type="full_text">
                <titles>
                  <title>A finite-difference iterative solver of the Helmholtz equation for frequency-domain seismic wave modeling and full-waveform inversion</title>
                </titles>
                <contributors>
                  <person_name sequence="first" contributor_role="author">
                    <given_name>Xingguo</given_name>
                    <surname>Huang</surname>
                    <affiliations>
                      <institution>
                        <institution_name>Jilin University 1 , College of Instrumentation and Electrical Engineering, and Key Lab of Geo-Exploration Instrumentation (Ministry of Education), Changchun 130026, China. E-mail: xingguo.huang19@gmail.com (corresponding author).</institution_name>
                      </institution>
                    </affiliations>
                    <ORCID>http://orcid.org/0000-0001-9719-6297</ORCID>
                  </person_name>
                  <person_name sequence="additional" contributor_role="author">
                    <given_name>Stewart</given_name>
                    <surname>Greenhalgh</surname>
                    <affiliations>
                      <institution>
                        <institution_name>Swiss Federal Institute of Technology (ETH) Zurich 2 , Institute of Geophysics, Department of Earth Sciences, 8092 Zurich, Switzerland. E-mail: gstewart@retired.ethz.ch .</institution_name>
                      </institution>
                    </affiliations>
                  </person_name>
                </contributors>
                <jats:abstract xmlns:jats="http://www.ncbi.nlm.nih.gov/JATS1">
                  <jats:title>ABSTRACT</jats:title>
                  <jats:p>We have developed a finite-difference iterative solver of the Helmholtz equation for seismic modeling and inversion in the frequency domain. The iterative solver involves the shifted Laplacian operator and two-level preconditioners. It is based on the application of the preconditioners to the Krylov subspace stabilized biconjugate gradient method. A critical factor for the iterative solver is the introduction of a new preconditioner into the Krylov subspace iteration method to solve the linear equation system resulting from the discretization of the Helmholtz equation. This new preconditioner is based on a reformulation of an integral equation-based convergent Born series for the Lippmann-Schwinger equation to an equivalent differential equation. We have determined that our iterative solver combined with the novel preconditioner when incorporated with the finite-difference method accelerates the convergence of the Krylov subspace iteration method for frequency-domain seismic wave modeling. A comparison of a direct solver, a one-level Krylov subspace iterative solver, and our two-level iterative solver verified the accuracy and accelerated convergence of the new scheme. Extensive tests in full-waveform inversion demonstrate the solver’s applicability to such problems.</jats:p>
                </jats:abstract>
                <publication_date media_type="online">
                  <month>02</month>
                  <day>23</day>
                  <year>2021</year>
                </publication_date>
                <publication_date media_type="print">
                  <month>03</month>
                  <day>01</day>
                  <year>2021</year>
                </publication_date>
                <pages>
                  <first_page>T107</first_page>
                  <last_page>T116</last_page>
                </pages>
                <crossmark>
                  <crossmark_version>1</crossmark_version>
                  <crossmark_policy>10.1190/crossmark-policy</crossmark_policy>
                  <crossmark_domains>
                    <crossmark_domain>
                      <domain>library.seg.org</domain>
                    </crossmark_domain>
                  </crossmark_domains>
                  <crossmark_domain_exclusive>true</crossmark_domain_exclusive>
                  <custom_metadata>
                    <assertion name="received" label="Received" group_name="publication_history" group_label="Publication History" order="0">2020-06-24</assertion>
                    <assertion name="revised" label="Revised" group_name="publication_history" group_label="Publication History" order="1">2020-12-07</assertion>
                    <assertion name="accepted" label="Accepted" group_name="publication_history" group_label="Publication History" order="2">2020-12-08</assertion>
                    <assertion name="published" label="Published" group_name="publication_history" group_label="Publication History" order="3">2021-02-23</assertion>
                  </custom_metadata>
                </crossmark>
                <doi_data>
                  <doi>10.1190/geo2020-0411.1</doi>
                  <resource>https://pubs.geoscienceworld.org/geophysics/article/86/2/T107/594902/A-finite-difference-iterative-solver-of-the</resource>
                  <collection property="syndication">
                    <item>
                      <resource mime_type="application/pdf" content_version="vor">https://pubs.geoscienceworld.org/seg/geophysics/article-pdf/86/2/T107/5264488/geo-2020-0411.1.pdf</resource>
                    </item>
                  </collection>
                  <collection property="crawler-based">
                    <item crawler="iParadigms">
                      <resource>https://pubs.geoscienceworld.org/seg/geophysics/article-pdf/86/2/T107/5264488/geo-2020-0411.1.pdf</resource>
                    </item>
                  </collection>
                  <collection property="list-based" multi-resolution="unlock">
                    <item label="geoscienceworld" setbyID="silver_mr">
                      <resource>https://pubs.geoscienceworld.org/geophysics/article/86/2/t107/594902/a-finite-difference-iterative-solver-of-the</resource>
                    </item>
                  </collection>
                </doi_data>
                <citation_list>
                  <citation key="2026041612394669400_r1">
                    <volume_title>Quantitative seismology: Theory and methods</volume_title>
                    <author>Aki</author>
                    <cYear>1980</cYear>
                  </citation>
                  <citation key="2026041612394669400_r2">
                    <issn>0045-7825</issn>
                    <journal_title>Computer Methods in Applied Mechanics and Engineering</journal_title>
                    <author>Amestoy</author>
                    <volume>184</volume>
                    <first_page>501</first_page>
                    <cYear>2000</cYear>
                    <doi provider="crossref">10.1016/S0045-7825(99)00242-X</doi>
                    <article_title>Multifrontal parallel distributed symmetric and unsymmetric solvers</article_title>
                  </citation>
                  <citation key="2026041612394669400_r3">
                    <issn>0021-9991</issn>
                    <journal_title>Journal of Computational Physics</journal_title>
                    <author>Belonosov</author>
                    <volume>345</volume>
                    <first_page>330</first_page>
                    <cYear>2017</cYear>
                    <doi provider="crossref">10.1016/j.jcp.2017.05.026</doi>
                    <article_title>An iterative solver for the 3D Helmholtz equation</article_title>
                  </citation>
                  <citation key="2026041612394669400_r4">
                    <issn>0895-4798</issn>
                    <journal_title>SIAM Journal on Matrix Analysis and Applications</journal_title>
                    <author>Davis</author>
                    <volume>18</volume>
                    <first_page>140</first_page>
                    <cYear>1997</cYear>
                    <doi provider="crossref">10.1137/S0895479894246905</doi>
                    <article_title>An unsymmetric-pattern multifrontal method for sparse LU factorization</article_title>
                  </citation>
                  <citation key="2026041612394669400_r5">
                    <journal_title>Electronic Transactions on Numerical Analysis</journal_title>
                    <author>Erlangga</author>
                    <volume>31</volume>
                    <first_page>403</first_page>
                    <cYear>2008</cYear>
                    <article_title>On a multilevel Krylov method for the Helmholtz equation preconditioned by a shifted Laplacian</article_title>
                  </citation>
                  <citation key="2026041612394669400_r6">
                    <issn>1064-8275</issn>
                    <journal_title>SIAM Journal on Scientific Computing</journal_title>
                    <author>Erlangga</author>
                    <volume>27</volume>
                    <first_page>1471</first_page>
                    <cYear>2006</cYear>
                    <doi provider="crossref">10.1137/040615195</doi>
                    <article_title>A novel multigrid based preconditioner for heterogeneous Helmholtz problems</article_title>
                  </citation>
                  <citation key="2026041612394669400_r7">
                    <volume_title>Why it is difficult to solve Helmholtz problems with classical iterative methods: Numerical analysis of multiscale problems</volume_title>
                    <author>Ernst</author>
                    <first_page>325</first_page>
                    <cYear>2012</cYear>
                  </citation>
                  <citation key="2026041612394669400_r8">
                    <issn>0148-0227</issn>
                    <journal_title>Journal of Geophysical Research</journal_title>
                    <author>Futterman</author>
                    <volume>67</volume>
                    <first_page>5279</first_page>
                    <cYear>1962</cYear>
                    <doi provider="crossref">10.1029/JZ067i013p05279</doi>
                    <article_title>Dispersive body waves</article_title>
                  </citation>
                  <citation key="2026041612394669400_r9">
                    <issn>0036-1429</issn>
                    <journal_title>SIAM Journal on Numerical Analysis</journal_title>
                    <author>George</author>
                    <volume>14</volume>
                    <first_page>161</first_page>
                    <cYear>1977</cYear>
                    <doi provider="crossref">10.1137/0714011</doi>
                    <article_title>Numerical experiments using dissection methods to solve n by n grid problems</article_title>
                  </citation>
                  <citation key="2026041612394669400_r10">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Huang</author>
                    <volume>85</volume>
                    <issue>4</issue>
                    <first_page>C125</first_page>
                    <cYear>2020</cYear>
                    <article_title>Bayesian seismic full waveform inversion in anisotropic elastic media using iterated extended Kalman filter</article_title>
                  </citation>
                  <citation key="2026041612394669400_r11">
                    <issn>1815-2406</issn>
                    <journal_title>Communications in Computational Physics</journal_title>
                    <author>Huang</author>
                    <volume>27</volume>
                    <first_page>1</first_page>
                    <cYear>2020</cYear>
                    <doi provider="crossref">10.4208/cicp.2020.swsii.review</doi>
                    <article_title>Target-oriented inversion of time-lapse seismic waveform data</article_title>
                  </citation>
                  <citation key="2026041612394669400_r12">
                    <journal_title>Journal of Geophysics and Engineering</journal_title>
                    <author>Huang</author>
                    <volume>17</volume>
                    <first_page>277</first_page>
                    <cYear>2020</cYear>
                    <doi provider="crossref">10.1093/jge/gxz105</doi>
                    <article_title>On the applicability of a renormalized Born series for seismic wavefield modelling in strongly scattering media</article_title>
                  </citation>
                  <citation key="2026041612394669400_r13">
                    <issn>0956-540X</issn>
                    <journal_title>Geophysical Journal International</journal_title>
                    <author>Hustedt</author>
                    <volume>157</volume>
                    <first_page>1269</first_page>
                    <cYear>2004</cYear>
                    <doi provider="crossref">10.1111/j.1365-246X.2004.02289.x</doi>
                    <article_title>Mixed-grid and staggered-grid finite difference methods for frequency domain acoustic wave modelling</article_title>
                  </citation>
                  <citation key="2026041612394669400_r14">
                    <issn>0956-540X</issn>
                    <journal_title>Geophysical Journal International</journal_title>
                    <author>Jakobsen</author>
                    <volume>222</volume>
                    <first_page>743</first_page>
                    <cYear>2020</cYear>
                    <doi provider="crossref">10.1093/gji/ggaa159</doi>
                    <article_title>Homotopy analysis of the Lippmann-Schwinger equation for seismic wavefield modeling in strongly scattering media</article_title>
                  </citation>
                  <citation key="2026041612394669400_r15">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Jo</author>
                    <volume>61</volume>
                    <first_page>529</first_page>
                    <cYear>1996</cYear>
                    <doi provider="crossref">10.1190/1.1443979</doi>
                    <article_title>An optimal 9-point, finite difference, frequency-space 2D scalar extrapolator</article_title>
                  </citation>
                  <citation key="2026041612394669400_r16">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Kostin</author>
                    <volume>84</volume>
                    <issue>4</issue>
                    <first_page>T207</first_page>
                    <cYear>2019</cYear>
                    <doi provider="crossref">10.1190/geo2018-0465.1</doi>
                    <article_title>Direct frequency-domain 3D acoustic solver with intermediate data compression benchmarked against time-domain modeling for FWI applications</article_title>
                  </citation>
                  <citation key="2026041612394669400_r17">
                    <journal_title>Computational Mathematics and Mathematical Physics</journal_title>
                    <author>Kostin</author>
                    <volume>60</volume>
                    <first_page>641</first_page>
                    <cYear>2020</cYear>
                    <doi provider="crossref">10.1134/S0965542520040119</doi>
                    <article_title>Optimization of a finite-difference scheme for numerical solution of the Helmholtz equation</article_title>
                  </citation>
                  <citation key="2026041612394669400_r18">
                    <unstructured_citation>Lailly
              P.
            
          , 1983, The seismic inverse problem as a sequence of before stack migrations: Conference on Inverse Scattering, Theory and Application, Society for Industrial and Applied Mathematics, Extended Abstracts, 206–220.</unstructured_citation>
                  </citation>
                  <citation key="2026041612394669400_r19">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Li</author>
                    <volume>80</volume>
                    <issue>3</issue>
                    <first_page>T101</first_page>
                    <cYear>2015</cYear>
                    <doi provider="crossref">10.1190/geo2014-0480.1</doi>
                    <article_title>2D and 3D frequency-domain elastic wave modeling in complex media with a parallel iterative solver</article_title>
                  </citation>
                  <citation key="2026041612394669400_r20">
                    <issn>0016-8025</issn>
                    <journal_title>Geophysical Prospecting</journal_title>
                    <author>Liu</author>
                    <volume>67</volume>
                    <first_page>1732</first_page>
                    <cYear>2019</cYear>
                    <doi provider="crossref">10.1111/1365-2478.12788</doi>
                    <article_title>Perfectly matched layer boundary conditions for frequency-domain acoustic wave simulation in the mesh-free discretization</article_title>
                  </citation>
                  <citation key="2026041612394669400_r21">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Marfurt</author>
                    <volume>49</volume>
                    <first_page>533</first_page>
                    <cYear>1984</cYear>
                    <doi provider="crossref">10.1190/1.1441689</doi>
                    <article_title>Accuracy of finite-difference and finite-element modeling of the scalar and elastic wave equation</article_title>
                  </citation>
                  <citation key="2026041612394669400_r22">
                    <issn>0956-540X</issn>
                    <journal_title>Geophysical Journal International</journal_title>
                    <author>Operto</author>
                    <volume>213</volume>
                    <first_page>2037</first_page>
                    <cYear>2018</cYear>
                    <doi provider="crossref">10.1093/gji/ggy103</doi>
                    <article_title>On the role of density and attenuation in three-dimensional multiparameter viscoacoustic VTI frequency-domain FWI: An OBC case study from the North Sea</article_title>
                  </citation>
                  <citation key="2026041612394669400_r23">
                    <issn>0956-540X</issn>
                    <journal_title>Geophysical Journal International</journal_title>
                    <author>Operto</author>
                    <volume>202</volume>
                    <first_page>1362</first_page>
                    <cYear>2015</cYear>
                    <doi provider="crossref">10.1093/gji/ggv226</doi>
                    <article_title>Efficient 3-D frequency-domain mono-parameter full-waveform inversion of ocean-bottom cable data: Application to Valhall in the visco-acoustic vertical transverse isotropic approximation</article_title>
                  </citation>
                  <citation key="2026041612394669400_r24">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Operto</author>
                    <volume>72</volume>
                    <issue>5</issue>
                    <first_page>SM195</first_page>
                    <cYear>2007</cYear>
                    <doi provider="crossref">10.1190/1.2759835</doi>
                    <article_title>3D finite-difference frequency-domain modeling of visco-acoustic wave propagation using a massively parallel direct solver: A feasibility study</article_title>
                  </citation>
                  <citation key="2026041612394669400_r25">
                    <issn>0021-9991</issn>
                    <journal_title>Journal of Computational Physics</journal_title>
                    <author>Osnabrugge</author>
                    <volume>322</volume>
                    <first_page>113</first_page>
                    <cYear>2016</cYear>
                    <doi provider="crossref">10.1016/j.jcp.2016.06.034</doi>
                    <article_title>A convergent Born series for solving the inhomogeneous Helmholtz equation in arbitrarily large media</article_title>
                  </citation>
                  <citation key="2026041612394669400_r26">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Petrov</author>
                    <volume>77</volume>
                    <issue>4</issue>
                    <first_page>T137</first_page>
                    <cYear>2012</cYear>
                    <doi provider="crossref">10.1190/geo2011-0238.1</doi>
                    <article_title>3D finite-difference modeling of elastic wave propagation in the Laplace-Fourier domain</article_title>
                  </citation>
                  <citation key="2026041612394669400_r27">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Plessix</author>
                    <volume>72</volume>
                    <issue>5</issue>
                    <first_page>SM185</first_page>
                    <cYear>2007</cYear>
                    <doi provider="crossref">10.1190/1.2738849</doi>
                    <article_title>A Helmholtz iterative solver for 3D seismic imaging problems</article_title>
                  </citation>
                  <citation key="2026041612394669400_r28">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Plessix</author>
                    <volume>74</volume>
                    <issue>6</issue>
                    <first_page>WCC53</first_page>
                    <cYear>2009</cYear>
                    <doi provider="crossref">10.1190/1.3211198</doi>
                    <article_title>Three-dimensional frequency-domain full waveform inversion with an iterative solver</article_title>
                  </citation>
                  <citation key="2026041612394669400_r29">
                    <journal_title>First Break</journal_title>
                    <author>Plessix</author>
                    <volume>28</volume>
                    <first_page>71</first_page>
                    <cYear>2010</cYear>
                    <doi provider="crossref">10.3997/1365-2397.2010013</doi>
                    <article_title>Full waveform inversion of a deep water ocean bottom seismometer dataset</article_title>
                  </citation>
                  <citation key="2026041612394669400_r30">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Pratt</author>
                    <volume>64</volume>
                    <first_page>888</first_page>
                    <cYear>1999</cYear>
                    <doi provider="crossref">10.1190/1.1444597</doi>
                    <article_title>Seismic waveform inversion in the frequency domain — Part 1: Theory and verification in a physical scale model</article_title>
                  </citation>
                  <citation key="2026041612394669400_r31">
                    <issn>0016-8025</issn>
                    <journal_title>Geophysical Prospecting</journal_title>
                    <author>Pratt</author>
                    <volume>38</volume>
                    <first_page>287</first_page>
                    <cYear>1990</cYear>
                    <doi provider="crossref">10.1111/j.1365-2478.1990.tb01846.x</doi>
                    <article_title>Inverse theory applied to multi-source cross-hole tomography — Part 1: Acoustic wave-equation method</article_title>
                  </citation>
                  <citation key="2026041612394669400_r32">
                    <journal_title>Journal of Geophysics and Engineering</journal_title>
                    <author>Ren</author>
                    <volume>10</volume>
                    <cYear>2013</cYear>
                    <doi provider="crossref">10.1088/1742-2132/10/5/054003</doi>
                    <article_title>A hybrid absorbing boundary condition for frequency-domain finite-difference modelling</article_title>
                  </citation>
                  <citation key="2026041612394669400_r33">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Riyanti</author>
                    <volume>71</volume>
                    <issue>5</issue>
                    <first_page>E57</first_page>
                    <cYear>2006</cYear>
                    <doi provider="crossref">10.1190/1.2231109</doi>
                    <article_title>A new iterative solver for the time-harmonic wave equation</article_title>
                  </citation>
                  <citation key="2026041612394669400_r34">
                    <volume_title>Iterative methods for sparse linear systems</volume_title>
                    <author>Saad</author>
                    <cYear>2003</cYear>
                    <doi provider="crossref">10.1137/1.9780898718003</doi>
                  </citation>
                  <citation key="2026041612394669400_r35">
                    <issn>1064-8275</issn>
                    <journal_title>SIAM Journal on Scientific Computing</journal_title>
                    <author>Saad</author>
                    <volume>7</volume>
                    <first_page>856</first_page>
                    <cYear>1986</cYear>
                    <doi provider="crossref">10.1137/0907058</doi>
                    <article_title>GMRES: A generalized minimal residual algorithm for solving non-symmetric linear systems</article_title>
                  </citation>
                  <citation key="2026041612394669400_r36">
                    <issn>0165-2125</issn>
                    <journal_title>Wave Motion</journal_title>
                    <author>Saenger</author>
                    <volume>31</volume>
                    <first_page>77</first_page>
                    <cYear>2000</cYear>
                    <doi provider="crossref">10.1016/S0165-2125(99)00023-2</doi>
                    <article_title>Modeling the propagation of elastic waves using a modified finite-difference grid</article_title>
                  </citation>
                  <citation key="2026041612394669400_r37">
                    <issn>0021-9991</issn>
                    <journal_title>Journal of Computational Physics</journal_title>
                    <author>Sheikh</author>
                    <volume>322</volume>
                    <first_page>473</first_page>
                    <cYear>2016</cYear>
                    <doi provider="crossref">10.1016/j.jcp.2016.06.025</doi>
                    <article_title>Accelerating the shifted Laplace preconditioner for the Helmholtz equation by multilevel deflation</article_title>
                  </citation>
                  <citation key="2026041612394669400_r38">
                    <journal_title>Electronic Transactions on Numerical Analysis</journal_title>
                    <author>Sleijpen</author>
                    <volume>1</volume>
                    <first_page>11</first_page>
                    <cYear>1993</cYear>
                    <article_title>BiCGSTAB (l) for linear equations involving asymmetric matrices with complex spectrum</article_title>
                  </citation>
                  <citation key="2026041612394669400_r39">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Štekl</author>
                    <volume>63</volume>
                    <first_page>1779</first_page>
                    <cYear>1998</cYear>
                    <doi provider="crossref">10.1190/1.1444472</doi>
                    <article_title>Accurate viscoelastic modeling by frequency-domain finite differences using rotated operators</article_title>
                  </citation>
                  <citation key="2026041612394669400_r40">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Tarantola</author>
                    <volume>49</volume>
                    <first_page>1259</first_page>
                    <cYear>1984</cYear>
                    <doi provider="crossref">10.1190/1.1441754</doi>
                    <article_title>Inversion of seismic reflection data in the acoustic approximation</article_title>
                  </citation>
                  <citation key="2026041612394669400_r41">
                    <journal_title>SIAM Journal on Scientific and Statistical Computing</journal_title>
                    <author>Van der Vorst</author>
                    <volume>13</volume>
                    <first_page>631</first_page>
                    <cYear>1992</cYear>
                    <doi provider="crossref">10.1137/0913035</doi>
                    <article_title>Bi-CGSTAB: A fast and smoothly converging variant of Bi-CG for the solution of non-symmetric linear systems</article_title>
                  </citation>
                  <citation key="2026041612394669400_r42">
                    <issn>0956-540X</issn>
                    <journal_title>Geophysical Journal International</journal_title>
                    <author>Van Leeuwen</author>
                    <volume>195</volume>
                    <first_page>661</first_page>
                    <cYear>2013</cYear>
                    <doi provider="crossref">10.1093/gji/ggt258</doi>
                    <article_title>Mitigating local minima in full-waveform inversion by expanding the search space</article_title>
                  </citation>
                  <citation key="2026041612394669400_r43">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Virieux</author>
                    <volume>49</volume>
                    <first_page>1933</first_page>
                    <cYear>1984</cYear>
                    <doi provider="crossref">10.1190/1.1441605</doi>
                    <article_title>SH-wave propagation in heterogeneous media: Velocity stress finite difference method</article_title>
                  </citation>
                  <citation key="2026041612394669400_r44">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Virieux</author>
                    <volume>74</volume>
                    <issue>6</issue>
                    <first_page>WCC127</first_page>
                    <cYear>2009</cYear>
                    <doi provider="crossref">10.1190/1.3238367</doi>
                    <article_title>An overview of full waveform inversion in exploration geophysics</article_title>
                  </citation>
                  <citation key="2026041612394669400_r45">
                    <issn>0956-540X</issn>
                    <journal_title>Geophysical Journal International</journal_title>
                    <author>Wu</author>
                    <volume>210</volume>
                    <first_page>1981</first_page>
                    <cYear>2017</cYear>
                    <doi provider="crossref">10.1093/gji/ggx283</doi>
                    <article_title>Efficient scattering-angle enrichment for a nonlinear inversion of the background and perturbations components of a velocity model</article_title>
                  </citation>
                  <citation key="2026041612394669400_r46">
                    <issn>0016-8033</issn>
                    <journal_title>Geophysics</journal_title>
                    <author>Wu</author>
                    <volume>83</volume>
                    <issue>2</issue>
                    <first_page>C75</first_page>
                    <cYear>2018</cYear>
                    <doi provider="crossref">10.1190/geo2017-0618.1</doi>
                    <article_title>An efficient Helmholtz solver for acoustic transversely isotropic media</article_title>
                  </citation>
                  <citation key="2026041612394669400_r47">
                    <issn>0037-1106</issn>
                    <journal_title>Bulletin of the Seismological Society of America</journal_title>
                    <author>Yang</author>
                    <volume>94</volume>
                    <first_page>1982</first_page>
                    <cYear>2004</cYear>
                    <doi provider="crossref">10.1785/012003155</doi>
                    <article_title>An optimal nearly-analytic discrete method for 2-D acoustic and elastic wave equations</article_title>
                  </citation>
                  <citation key="2026041612394669400_r48">
                    <issn>0037-1106</issn>
                    <journal_title>Bulletin of the Seismological Society of America</journal_title>
                    <author>Yang</author>
                    <volume>96</volume>
                    <first_page>1114</first_page>
                    <cYear>2006</cYear>
                    <doi provider="crossref">10.1785/0120050080</doi>
                    <article_title>Optimal nearly analytic discrete approximation to the scalar wave equation</article_title>
                  </citation>
                </citation_list>
              </journal_article>
            </journal>
          </crossref>
        </doi_record>
      </query>
    </body>
  </query_result>
</crossref_result>