Group congruences on eventually inverse semigroups Gomes, Gracinda M.S. — 1992 Portugaliae mathematica
A P -theorem for inverse semigroups with zero. Gomes, Gracinda M.S.; Howie, John M. — 1996 Portugaliae Mathematica
The cardinal and the idempotent number of various monoids of transformations on a finite chain. Fernandes, Vítor H.; Gomes, Gracinda M.S.; Jesus, Manuel M. — 2011 Bulletin of the Malaysian Mathematical Sciences Society. Second Series