Publications
Semidirectly closed pseudovarieties of locally trivial semigroups. Semigroup Forum. 1990;40:315-323.Edit
The algebra of implicit operations. Algebra Universalis. 1989;26:16-32.Edit
Equations for pseudovarieties. In: Formal properties of finite automata and applications (Ramatuelle, 1988). Vol 386. Springer, Berlin; 1989. 1. p. 148-164p. (Lecture Notes in Comput. Sci.; vol 386).Edit
The join of the pseudovarieties of $\scr R$-trivial and $\scr L$-trivial monoids. J. Pure Appl. Algebra. 1989;60:129-137.Edit
On power varieties of semigroups. J. Algebra. 1989;120:1-17.Edit
Residually finite congruences and quasi-regular subsets in uniform algebras. Portugal. Math.. 1989;46:313-328.Edit
Semidirect products of pseudovarieties from the universal algebraist's point of view. J. Pure Appl. Algebra. 1989;60:113-128.Edit
A notion of branching rank for semilattices with descending chain condition. Order. 1988;4:397-409.Edit
On pseudovarieties of monoids. In: Semigroups, theory and applications (Oberwolfach, 1986). Vol 1320. Springer, Berlin; 1988. 1. p. 11-17p. (Lecture Notes in Math.; vol 1320).Edit
Some pseudovariety joins involving the pseudovariety of finite groups. Semigroup Forum. 1988;37:53-57.Edit
Implicit operations on certain classes of semigroups. In: Semigroups and their applications (Chico, Calif., 1986). Reidel, Dordrecht; 1987. 1. p. 1-11p. Edit
Residually finite congruences and quasiregular subsets in uniform algebras. In: Proceedings of the Second Meeting of Portuguese Algebraists (Portuguese) (Porto, 1987). Univ. Porto, Porto; 1987. 1. p. 11-31p. Edit
Minimal nonpermutative pseudovarieties of semigroups. I, II. Pacific J. Math.. 1986;121:257-270, 271-279.Edit
Power pseudovarieties of semigroups. I, II. Semigroup Forum. 1986;33:357-373, 375-390.Edit
Some order properties of the lattice of varieties of commutative semigroups. Canad. J. Math.. 1986;38:19-47.Edit
Minimal nonpermutative pseudovarieties of semigroups. III. Algebra Universalis. 1985;21:256-279.Edit
Some quasi-ordered classes of finite commutative semigroups. Semigroup Forum. 1985;32:189-200.Edit
Generalized varieties of commutative and nilpotent semigroups. Semigroup Forum. 1984;30:77-98.Edit
Some algorithms on the star operation applied to finite languages. Semigroup Forum. 1984;28:187-197.Edit
Overlapping of words in rational languages. In: Combinatorics on words (Waterloo, Ont., 1982). Academic Press, Toronto, ON; 1983. 1. p. 119-131p. Edit