Completions and injective hulls of E-reflexive inverse semigroups.
Completions for partially ordered semigroups.
Congruence relations on left canonic semigroups.
Constructing inverse monoids from small categories.
Construction and representation of regular semigroups.
Correction and supplement to "On a pull-back diagram for orthodox semigroups".
Crossed semimodules and Schreier internal categories in the category of monoids.
Epimorphisms and amalgams
Epimorphisms and dominions.
Epimorphisms, dominions and varieties of semigroups.
Epis from locally inverse semigroups are onto.
Extension theories for monoids.
Finite commutative monoids of open maps
Flatness and amalgamation in semigroups.
Flatness and projectivity in commutative regular semigroups.
Flatness in varieties of normal bands.
Flatness Properties of Monocyclic Acts.
Free products of normal bands.
Generalized Green's relations
Goldie's theorem for semigroups.