{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T21:50:56Z","timestamp":1767909056516,"version":"3.49.0"},"reference-count":9,"publisher":"Elsevier BV","issue":"2","license":[{"start":{"date-parts":[[1982,2,1]],"date-time":"1982-02-01T00:00:00Z","timestamp":381369600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2013,7,18]],"date-time":"2013-07-18T00:00:00Z","timestamp":1374105600000},"content-version":"vor","delay-in-days":11490,"URL":"https:\/\/www.elsevier.com\/open-access\/userlicense\/1.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Information and Control"],"published-print":{"date-parts":[[1982,2]]},"DOI":"10.1016\/s0019-9958(82)80028-4","type":"journal-article","created":{"date-parts":[[2005,1,14]],"date-time":"2005-01-14T14:44:53Z","timestamp":1105713893000},"page":"172-186","source":"Crossref","is-referenced-by-count":33,"title":["Test sets for context free languages and algebraic systems of equations over a free monoid"],"prefix":"10.1016","volume":"52","author":[{"given":"J.","family":"Albert","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"suffix":"II","given":"K.","family":"Culik","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J.","family":"Karhum\u00e4ki","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"78","reference":[{"key":"10.1016\/S0019-9958(82)80028-4_bib1","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/S0019-9958(80)90659-2","article-title":"Tests sets for homomorphism equivalence on context free languages","volume":"45","author":"Albert","year":"1980","journal-title":"Inform. and Control"},{"key":"10.1016\/S0019-9958(82)80028-4_bib2","series-title":"Formal Language Theory, Perspectives and Open Problems","first-page":"167","article-title":"Homomorphisms: Decidability, equality and test sets","author":"Culik","year":"1980"},{"key":"10.1016\/S0019-9958(82)80028-4_bib3","series-title":"Discrete Mathematics","article-title":"Systems of equations over a free monoid and Ehrenfeucht Conjecture","author":"Culik","year":"1982"},{"key":"10.1016\/S0019-9958(82)80028-4_bib4","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/0022-0000(78)90002-8","article-title":"On the decidability of homomorphism equivalence for languages","volume":"17","author":"Culik","year":"1978","journal-title":"J. Comput. System Sci."},{"key":"10.1016\/S0019-9958(82)80028-4_bib5","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1016\/0022-0000(80)90013-6","article-title":"Test sets and checking words for homomorphism equivalence","volume":"20","author":"Culik","year":"1980","journal-title":"J. Comput. System Sci."},{"key":"10.1016\/S0019-9958(82)80028-4_bib6","series-title":"Introduction to Formal Language Theory","author":"Harrison","year":"1978"},{"key":"10.1016\/S0019-9958(82)80028-4_bib7","series-title":"Introduction to Automata Theory, Languages and Computation","author":"Hopcroft","year":"1979"},{"issue":"145","key":"10.1016\/S0019-9958(82)80028-4_bib8","first-page":"148","article-title":"The problem of solvability of equations in a free semigroup","volume":"103","author":"Makanin","year":"1977","journal-title":"Mat. Sb."},{"key":"10.1016\/S0019-9958(82)80028-4_bib9","series-title":"Formal Languages","author":"Salomaa","year":"1973"}],"container-title":["Information and Control"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0019995882800284?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0019995882800284?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2019,1,30]],"date-time":"2019-01-30T02:51:35Z","timestamp":1548816695000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0019995882800284"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1982,2]]},"references-count":9,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1982,2]]}},"alternative-id":["S0019995882800284"],"URL":"https:\/\/doi.org\/10.1016\/s0019-9958(82)80028-4","relation":{},"ISSN":["0019-9958"],"issn-type":[{"value":"0019-9958","type":"print"}],"subject":[],"published":{"date-parts":[[1982,2]]}}}