{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T15:16:51Z","timestamp":1774624611444,"version":"3.50.1"},"reference-count":8,"publisher":"Elsevier BV","issue":"3","license":[{"start":{"date-parts":[[1973,7,1]],"date-time":"1973-07-01T00:00:00Z","timestamp":110332800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2013,7,17]],"date-time":"2013-07-17T00:00:00Z","timestamp":1374019200000},"content-version":"vor","delay-in-days":14626,"URL":"https:\/\/www.elsevier.com\/open-access\/userlicense\/1.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Discrete Mathematics"],"published-print":{"date-parts":[[1973,7]]},"DOI":"10.1016\/0012-365x(73)90142-8","type":"journal-article","created":{"date-parts":[[2002,7,25]],"date-time":"2002-07-25T23:33:13Z","timestamp":1027639993000},"page":"253-260","source":"Crossref","is-referenced-by-count":32,"title":["A seven-color theorem on the sphere"],"prefix":"10.1016","volume":"5","author":[{"given":"Hudson V.","family":"Kronk","sequence":"first","affiliation":[]},{"given":"John","family":"Mitchem","sequence":"additional","affiliation":[]}],"member":"78","reference":[{"key":"10.1016\/0012-365X(73)90142-8_BIB1","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1112\/jlms\/s1-42.1.226","article-title":"The colour numbers of complete graphs","volume":"42","author":"Behzad","year":"1967","journal-title":"J. London Math. Soc."},{"key":"10.1016\/0012-365X(73)90142-8_BIB2","first-page":"133","article-title":"Graph theory","author":"Harary","year":"1969"},{"key":"10.1016\/0012-365X(73)90142-8_BIB3","series-title":"Beitr\u00e4ge zur Graphen-theorie","first-page":"81","article-title":"Verallgemeinerte Farbenzahlen","author":"Izbicki","year":"1968"},{"key":"10.1016\/0012-365X(73)90142-8_BIB4","first-page":"671","article-title":"The chromatic class and location of a graph on a closed surface","volume":"7","author":"Mel'nikov","year":"1970","journal-title":"Mat. Zametki"},{"key":"10.1016\/0012-365X(73)90142-8_BIB5","series-title":"Theory of graphs","first-page":"265","article-title":"A six-colour problem on the sphere","author":"Ringel","year":"1968"},{"key":"10.1016\/0012-365X(73)90142-8_BIB6","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1007\/BF02996313","article-title":"Ein Sechs-farben-problem auf der Kugel","volume":"29","author":"Ringel","year":"1965","journal-title":"Abh. Math. Sem. Univ. Hamburg"},{"key":"10.1016\/0012-365X(73)90142-8_BIB7","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1073\/pnas.60.2.438","article-title":"Solution of the Heawood map-coloring problem","volume":"60","author":"Ringel","year":"1968","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"10.1016\/0012-365X(73)90142-8_BIB8","doi-asserted-by":"crossref","first-page":"157","DOI":"10.4153\/CMB-1961-019-4","article-title":"On the colouring of graphs","volume":"4","author":"Tutte","year":"1961","journal-title":"Canad. Math. Bull."}],"container-title":["Discrete Mathematics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:0012365X73901428?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:0012365X73901428?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2019,4,13]],"date-time":"2019-04-13T06:51:31Z","timestamp":1555138291000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/0012365X73901428"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1973,7]]},"references-count":8,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1973,7]]}},"alternative-id":["0012365X73901428"],"URL":"https:\/\/doi.org\/10.1016\/0012-365x(73)90142-8","relation":{},"ISSN":["0012-365X"],"issn-type":[{"value":"0012-365X","type":"print"}],"subject":[],"published":{"date-parts":[[1973,7]]}}}