{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2023,9,19]],"date-time":"2023-09-19T05:30:42Z","timestamp":1695101442163},"reference-count":12,"publisher":"Elsevier BV","issue":"3","license":[{"start":{"date-parts":[[1973,3,1]],"date-time":"1973-03-01T00:00:00Z","timestamp":99792000000},"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":14748,"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":[[1973,3]]},"DOI":"10.1016\/s0012-365x(73)80004-4","type":"journal-article","created":{"date-parts":[[2005,12,15]],"date-time":"2005-12-15T17:59:32Z","timestamp":1134669572000},"page":"233-241","source":"Crossref","is-referenced-by-count":2,"title":["Free and almost-free subsemigroups of a free semigroup"],"prefix":"10.1016","volume":"4","author":[{"given":"Ronald V.","family":"Book","sequence":"first","affiliation":[]}],"member":"78","reference":[{"key":"10.1016\/S0012-365X(73)80004-4_bib1","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1307\/mmj\/1028999307","article-title":"Subsemigroups of a free semigroup","volume":"12","author":"Blum","year":"1965","journal-title":"Michigan Math. J."},{"key":"10.1016\/S0012-365X(73)80004-4_bib2","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1109\/T-C.1971.223204","article-title":"Ambiguity in graphs and expressions","volume":"C-20","author":"Book","year":"1971","journal-title":"IEEE Trans. Computers"},{"key":"10.1016\/S0012-365X(73)80004-4_bib3","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1145\/321406.321409","article-title":"Roots of star events","volume":"14","author":"Brzozowski","year":"1967","journal-title":"J. Assoc. Comput. Mach."},{"key":"10.1016\/S0012-365X(73)80004-4_bib4","article-title":"The algebraic theory of semigroups","volume":"7","author":"Clifford","year":"1961"},{"key":"10.1016\/S0012-365X(73)80004-4_bib5","series-title":"Proc. Am. Math. Soc.","first-page":"347","article-title":"On subsemigroups of free semigroups","author":"Cohn","year":"1962"},{"key":"10.1016\/S0012-365X(73)80004-4_bib6","article-title":"On information lossless automata","author":"Even","year":"1963"},{"key":"10.1016\/S0012-365X(73)80004-4_bib7","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1109\/TIT.1963.1057817","article-title":"Tests for unique decipherability, IEEE Trans","volume":"9","author":"Even","year":"1963","journal-title":"Inform. Theory"},{"key":"10.1016\/S0012-365X(73)80004-4_bib8","series-title":"Mathematical theory of context-free languages","author":"Ginsburg","year":"1966"},{"key":"10.1016\/S0012-365X(73)80004-4_bib9","series-title":"Formal languages and their relation to automata","author":"Hopcroft","year":"1969"},{"key":"10.1016\/S0012-365X(73)80004-4_bib10","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1147\/rd.32.0114","article-title":"Finite automata and their decision problems","volume":"3","author":"Rabin","year":"1959","journal-title":"IBM J. Res. Develop."},{"key":"10.1016\/S0012-365X(73)80004-4_bib11","series-title":"Theory of recursive functions and effective computability","author":"Rogers","year":"1967"},{"key":"10.1016\/S0012-365X(73)80004-4_bib12","first-page":"104","article-title":"A necessary and sufficient condition for unique decomposition of coded messages","author":"Sardinas","year":"1953","journal-title":"IRE Convention Record"}],"container-title":["Discrete Mathematics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0012365X73800044?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0012365X73800044?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2019,1,19]],"date-time":"2019-01-19T15:00:05Z","timestamp":1547910005000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0012365X73800044"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1973,3]]},"references-count":12,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1973,3]]}},"alternative-id":["S0012365X73800044"],"URL":"https:\/\/doi.org\/10.1016\/s0012-365x(73)80004-4","relation":{},"ISSN":["0012-365X"],"issn-type":[{"value":"0012-365X","type":"print"}],"subject":[],"published":{"date-parts":[[1973,3]]}}}