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@article{MOMA_1988__106_1_178400, author = {K.H. Hofmann and W.A.F. Ruppert}, title = {The {Foliation} of {Semigroups} by {Congruence} {Classes.}}, journal = {Monatshefte f\"ur Mathematik}, pages = {179--204}, publisher = {mathdoc}, volume = {106}, number = {1}, year = {1988}, zbl = {0671.22003}, url = {http://geodesic.mathdoc.fr/item/MOMA_1988__106_1_178400/} }
K.H. Hofmann; W.A.F. Ruppert. The Foliation of Semigroups by Congruence Classes.. Monatshefte für Mathematik, Tome 106 (1988) no. 1, pp. 179-204. http://geodesic.mathdoc.fr/item/MOMA_1988__106_1_178400/