On semilattices of groups whose arrows are epimorphisms. Abdallah, M.El-Ghali M.; Gab-Alla, L.N.; Elagan, Sayed K.M. — 2006 International Journal of Mathematics and Mathematical Sciences
Minimal conditions on Clifford semigroup congruences. Abdallah, M.El-Ghali M.; Gab-Alla, L.N.; Elagan, Sayed K.M. — 2006 International Journal of Mathematics and Mathematical Sciences