1. The Burnside Problem and Identities in Groups;Adian,1979
2. The free completely regular semigroup on a set;Clifford;J. Algebra,1979
3. Universal Algebra;Cohn,1965
4. The word problem for semigroups satisfying x3 = x;Gerhard,1978
5. Free completely regular semigroups. I. Representation;Gerhard;J. Algebra,1983