On some classes of point algebras
On some extrem properties of a class of simple groupoids.
On some properties of Brandt groupoids.
On the integration theorem for Lie groupoids
On the intersection graph of a commutative distributive groupoid
On the monoids of homomorphisms of semigroups with unity
On the Pexider equation.
On totally non-commutative convergence groupoids
One-element extensions of distributive groupoids
Ordered groupoids and étendues