Clifford, A. H., & Preston, G. B. (1964). The algebraic theory of semigroups. Providence, RI.: American Mathematical Society.
Παραπομπή Chicago StyleClifford, A. H., and G. B. Preston. The Algebraic Theory of Semigroups. Providence, RI.: American Mathematical Society, 1964.
Παραπομπή MLAClifford, A. H., and G. B. Preston. The Algebraic Theory of Semigroups. Providence, RI.: American Mathematical Society, 1964.
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