{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T15:41:07Z","timestamp":1762270867173},"reference-count":3,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[1988,3,1]],"date-time":"1988-03-01T00:00:00Z","timestamp":573177600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/www.springer.com\/tdm"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Combinatorica"],"published-print":{"date-parts":[[1988,3]]},"DOI":"10.1007\/bf02122562","type":"journal-article","created":{"date-parts":[[2005,10,29]],"date-time":"2005-10-29T06:29:39Z","timestamp":1130567379000},"page":"137-139","source":"Crossref","is-referenced-by-count":8,"title":["The edge-density of 4-critical planar graphs"],"prefix":"10.1007","volume":"8","author":[{"given":"B.","family":"Gr\u00fcnbaum","sequence":"first","affiliation":[]}],"member":"297","reference":[{"key":"BF02122562_CR1","first-page":"43","volume-title":"Theory of Graphs and its Applications (Proc. Symp. Smolenice 1963)","author":"T. Gallai","year":"1964","unstructured":"T. Gallai, Critical graphs.Theory of Graphs and its Applications (Proc. Symp. Smolenice 1963), Publ. House Czechoslovak Acad. Sci..Prague 1964, 43\u201345."},{"key":"BF02122562_CR2","first-page":"129","volume":"33","author":"G. Koester","year":"1984","unstructured":"G. Koester, Bemerkung zu einem Problem von H. Gr\u00f6tzsch.Wiss. Z. Univ. Halle,33 (1984), 129.","journal-title":"Wiss. Z. Univ. Halle"},{"key":"BF02122562_CR3","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1007\/BF02579365","volume":"5","author":"G. Koester","year":"1985","unstructured":"G. Koester, Note to a problem of T. Gallai and G. A. Dirac,Combinatorica.5 (1985), 227\u2013228.","journal-title":"Combinatorica"}],"container-title":["Combinatorica"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/link.springer.com\/content\/pdf\/10.1007\/BF02122562.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/link.springer.com\/article\/10.1007\/BF02122562\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/link.springer.com\/content\/pdf\/10.1007\/BF02122562","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,5,14]],"date-time":"2019-05-14T01:22:28Z","timestamp":1557796948000},"score":1,"resource":{"primary":{"URL":"http:\/\/link.springer.com\/10.1007\/BF02122562"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1988,3]]},"references-count":3,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1988,3]]}},"alternative-id":["BF02122562"],"URL":"https:\/\/doi.org\/10.1007\/bf02122562","relation":{},"ISSN":["0209-9683","1439-6912"],"issn-type":[{"value":"0209-9683","type":"print"},{"value":"1439-6912","type":"electronic"}],"subject":[],"published":{"date-parts":[[1988,3]]}}}