@article{GDZPPN001252275,
title = {Semigroups in which each -class contains at most one regular ...-class.},
journal = {Semigroup forum},
volume = {14},
year = {1977},
pages = {91-92},
zbl = {0372.54035},
url = {http://dml.mathdoc.fr/item/GDZPPN001252275}
}
Magill, K. D. jr. Semigroups in which each -class contains at most one regular ...-class.. Semigroup forum, Tome 14 (1977) pp. 91-92. http://gdmltest.u-ga.fr/item/GDZPPN001252275/