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 year         = "1997",
 title        = "Combinatorics of Words",
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 year         = "2002",
 title        = "Independent systems of equations",
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 booktitle    = "Algebraic Combinatorics on Words",
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 author       = "Juhani Karhum{\"a}ki and Aleksi Saarela",
 title        = "On maximal chains of systems of word equations",
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 author       = "M. Lothaire",
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 title        = "Combinatorics on Words",
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 year         = "2001",
 title        = "Variations on a theorem of {F}ine \& {W}ilf",
 booktitle    = "Proceedings of the 26th International Symposium on Mathematical Foundations of Computer Science",
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 author       = "Wojciech Plandowski",
 year         = "2003",
 title        = "Test sets for large families of languages",
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 author       = "Arto Salomaa",
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 title        = "The {E}hrenfeucht conjecture: a proof for language theorists",
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 author       = "Paavo Turakainen",
 year         = "1987",
 title        = "The equivalence of deterministic gsm replications on {$Q$}-rational languages is decidable",
 journal      = "Math. Systems Theory",
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 number       = "4",
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 doi          = "10.1007/BF01692070",
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