O zovšeobecněních pojmu grupy
On a class of groupoids
On a class of subdirectly irreducible groupoids
On cyclic hypergroups with period
On Finite-element Simple Extensions of a Countable Collection of Countable Groupoids
On Free Commutative Groupoids
On free commutative groupoids.
On representations of monoids as monoids of polynomials
On rings with zero divisors. Strong -groups
On splitting -systems
On the extension of transi-groups
On the general theory of m-groups
On the generalised equations of associativity and bisymmetry.
On -algebras
One-element extensions of distributive groupoids