Clifford, A. H., & Preston, G. B. (1961). Algebraic theory of semigroups V 1. American Mathematical Society.
Dyfyniad Arddull ChicagoClifford, A. H., and G. B. Preston. Algebraic Theory of Semigroups V 1. Rhode Island: American Mathematical Society, 1961.
Dyfyniad MLAClifford, A. H., and G. B. Preston. Algebraic Theory of Semigroups V 1. American Mathematical Society, 1961.
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