Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{SF_1975__10_134118, author = {A.H. Clifford}, title = {The partial groupoid of idempotents of a regular semigroup.}, journal = {Semigroup forum}, pages = {262--268}, publisher = {mathdoc}, volume = {10}, year = {1975}, zbl = {0299.20045}, url = {http://geodesic.mathdoc.fr/item/SF_1975__10_134118/} }
A.H. Clifford. The partial groupoid of idempotents of a regular semigroup.. Semigroup forum, Tome 10 (1975), pp. 262-268. http://geodesic.mathdoc.fr/item/SF_1975__10_134118/