Largest 2-generated subsemigroups of the symmetric inverse semigroup

Proceedings of the Edinburgh Mathematical Society, nº50 (2007), p.551-561

The idempotent-separating degree of a block-group

Semigroup Forum, nº76 (2008), pg.579-583

Abelian kernels of monoids of order-preserving maps and of some of its extensions

Semigroup Forum vol. 68 (2004), p. 335–356

Automorphisms of partial endomorphism semigroups

Publicationes Mathematicae Debrecen

Normally ordered semigroups

Glasgow Mathematical Journal, nº 50 (2008), p. 325-333