Author: Abrhan, Imrich

Abrhan, Imrich: On minimal ideals in semigroups with respect to their subsets. II. (English). Mathematica Slovaca, vol. 44 (1994), issue 4, pp. 463-478
Abrhan, Imrich; Satko, Ladislav: $r$-systems of unary algebras. I: On maximal and greatest $J$-classes of the direct product of unary algebras. (English). Mathematica Slovaca, vol. 44 (1994), issue 1, pp. 55-68
Abrhan, Imrich; Satko, Ladislav: $r$-systems of unary algebras. II: Maximal and minimal subalgebras of the direct products of unary algebras. (English). Mathematica Slovaca, vol. 44 (1994), issue 1, pp. 69-83