@article{GDZPPN002486407,
title = {The Foliation of Semigroups by Congruence Classes.},
journal = {Monatshefte f\"ur Mathematik},
volume = {105},
year = {1988},
pages = {179-204},
zbl = {0671.22003},
url = {http://dml.mathdoc.fr/item/GDZPPN002486407}
}
Hofmann, K.H.; Ruppert, W.A.F. The Foliation of Semigroups by Congruence Classes.. Monatshefte für Mathematik, Tome 105 (1988) pp. 179-204. http://gdmltest.u-ga.fr/item/GDZPPN002486407/