Ondrej Klíma, Libor Polák. Identity Problems, Solvability of Equations and Unification in Varieties of Semigroups Related to Varieties of Groups. In Werner Kuich, George Rahonis, editors, Algebraic Foundations in Computer Science - Essays Dedicated to Symeon Bozapalidis on the Occasion of His Retirement. Volume 7020 of Lecture Notes in Computer Science, pages 214-227, Springer, 2011. [doi]
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