Semigroup theoretical approach to normal ideals Tatsuhiko Saito (1987) Beiträge zur Algebra und Geometrie = Contributions to algebra and geometry
Semigroups and rings whose proper one-sided ideals are power joined Alessandra Cherubini, Ada Varisco (1984) Czechoslovak Mathematical Journal
Semigroups whose proper subsemigroups are duo Alessandra Cherubini, Ada Varisco (1984) Czechoslovak Mathematical Journal
Some properties of α -ideals and generalized α -ideals, n -semigroups and n -groups Antoni Chronowski (1994) Czechoslovak Mathematical Journal
Some remarks on Lorenzen r -group of partly ordered groups Jiří Močkoř, Angeliki Kontolatou (1996) Czechoslovak Mathematical Journal
Some results on ordered filters of implicative semigroups. Jun, Young Bae (2001) International Journal of Mathematics and Mathematical Sciences