{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T17:06:01Z","timestamp":1786122361036,"version":"3.56.0"},"reference-count":13,"publisher":"Springer Science and Business Media LLC","issue":"3","license":[{"start":{"date-parts":[[1996,9,1]],"date-time":"1996-09-01T00:00:00Z","timestamp":841536000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/www.springer.com\/tdm"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Stat Comput"],"published-print":{"date-parts":[[1996,9]]},"DOI":"10.1007\/bf00140873","type":"journal-article","created":{"date-parts":[[2004,10,31]],"date-time":"2004-10-31T21:28:52Z","timestamp":1099258132000},"page":"289-296","source":"Crossref","is-referenced-by-count":412,"title":["Unconstrained parametrizations for variance-covariance matrices"],"prefix":"10.1007","volume":"6","author":[{"given":"Jos\ufffd C.","family":"Pinheiro","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Douglas M.","family":"Bates","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","reference":[{"issue":"4","key":"CR1","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1137\/0908055","volume":"8","author":"T. W. Anderson","year":"1987","unstructured":"Anderson, T. W., Olkin, I. and Underhill, L. G. (1987) Generation of random orthogonal matrices. SIAM Journal on Scientific and Statistical Computing, 8(4), 625?9.","journal-title":"SIAM Journal on Scientific and Statistical Computing"},{"key":"CR2","doi-asserted-by":"crossref","DOI":"10.1002\/9780470316757","volume-title":"Nonlinear Regression Analysis and Its Applications","author":"D. M. Bates","year":"1988","unstructured":"Bates, D. M. and Watts, D. G. (1988) Nonlinear Regression Analysis and Its Applications. Wiley, New York."},{"key":"CR3","volume-title":"Numerical Methods for Unconstrained Optimization and Nonlinear Equations","author":"J. E. Dennis Jr.","year":"1983","unstructured":"Dennis, Jr., J. E. and Schnabel, R. B. (1983) Numerical Methods for Unconstrained Optimization and Nonlinear Equations. Prentice-Hall, Englewood Cliffs, NJ."},{"issue":"4","key":"CR4","doi-asserted-by":"crossref","first-page":"805","DOI":"10.2307\/2530695","volume":"42","author":"R. I. Jennrich","year":"1986","unstructured":"Jennrich, R. I. and Schluchter, M. D. (1986) Unbalanced repeated measures models with structural covariance matrices. Biometrics, 42(4), 805?20.","journal-title":"Biometrics"},{"issue":"2","key":"CR5","doi-asserted-by":"crossref","first-page":"328","DOI":"10.1137\/0715022","volume":"15","author":"D. L. B. Jupp","year":"1978","unstructured":"Jupp, D. L. B. (1978) Approximation to data by splines with free knots. SIAM Journal of Numerical Analysis, 15(2), 328?43.","journal-title":"SIAM Journal of Numerical Analysis"},{"key":"CR6","doi-asserted-by":"crossref","first-page":"963","DOI":"10.2307\/2529876","volume":"38","author":"N. M. Laird","year":"1982","unstructured":"Laird, N. M. and Ware, J. H. (1982) Random-effects models for longitudinal data. Biometrics, 38, 963?74.","journal-title":"Biometrics"},{"key":"CR7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1214\/aos\/1176349012","volume":"21","author":"T. Leonard","year":"1993","unstructured":"Leonard, T. and Hsu, J. S. J. (1993) Bayesian inference for a covariance matrix. Annals of Statistics, 21, 1?25.","journal-title":"Annals of Statistics"},{"key":"CR8","first-page":"1014","volume":"83","author":"M. J. Lindstrom","year":"1988","unstructured":"Lindstrom, M. J. and Bates, D. M. (1988) Newton-Raphson and EM algorithms for linear mixed-effects models for repeated-measures data. Journal of the American Statistical Association, 83, 1014?22.","journal-title":"Journal of the American Statistical Association"},{"key":"CR9","doi-asserted-by":"crossref","first-page":"673","DOI":"10.2307\/2532087","volume":"46","author":"M. J. Lindstrom","year":"1990","unstructured":"Lindstrom, M. J. and Bates, D. M. (1990) Nonlinear mixed effects models for repeated measures data. Biometrics, 46, 673?87.","journal-title":"Biometrics"},{"key":"CR10","unstructured":"Pinheiro, J. C. (1994) Topics in Mixed Effects Models. PhD thesis, University of Wisconsin-Madison."},{"key":"CR11","doi-asserted-by":"crossref","unstructured":"Pinheiro, J. C. and Bates, D. M. (1995) Model building for nonlinear mixed-effects models. Technical Report 91, Department of Biostatistics, University of Wisconsin-Madison.","DOI":"10.2307\/1390625"},{"key":"CR12","doi-asserted-by":"crossref","DOI":"10.1002\/9780470316436","volume-title":"Linear Statistical Inference and Its Applications","author":"C. R. Rao","year":"1973","unstructured":"Rao, C. R. (1973) Linear Statistical Inference and Its Applications, 2nd edn. Wiley, New York.","edition":"2nd edn."},{"key":"CR13","volume-title":"Elements of Statistical Computing","author":"R. A. Thisted","year":"1988","unstructured":"Thisted, R. A. (1988) Elements of Statistical Computing. Chapman & Hall, London."}],"container-title":["Statistics and Computing"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/link.springer.com\/content\/pdf\/10.1007\/BF00140873.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/link.springer.com\/article\/10.1007\/BF00140873\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/link.springer.com\/content\/pdf\/10.1007\/BF00140873","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,4,3]],"date-time":"2019-04-03T02:00:40Z","timestamp":1554256840000},"score":1,"resource":{"primary":{"URL":"http:\/\/link.springer.com\/10.1007\/BF00140873"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1996,9]]},"references-count":13,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1996,9]]}},"alternative-id":["BF00140873"],"URL":"https:\/\/doi.org\/10.1007\/bf00140873","relation":{},"ISSN":["0960-3174","1573-1375"],"issn-type":[{"value":"0960-3174","type":"print"},{"value":"1573-1375","type":"electronic"}],"subject":[],"published":{"date-parts":[[1996,9]]}}}