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@article{SF_1977__14_186361, author = {C.C. Edwards}, title = {The greatest idempotent separating congruence on an ....-unipotent semigroup.}, journal = {Semigroup forum}, pages = {127--136}, publisher = {mathdoc}, volume = {14}, year = {1977}, zbl = {0368.20045}, url = {http://geodesic.mathdoc.fr/item/SF_1977__14_186361/} }
C.C. Edwards. The greatest idempotent separating congruence on an ....-unipotent semigroup.. Semigroup forum, Tome 14 (1977), pp. 127-136. http://geodesic.mathdoc.fr/item/SF_1977__14_186361/