Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{SF_1979__18_134362, author = {E.M. Norris}, title = {The structure of an idempotent relation.}, journal = {Semigroup forum}, pages = {319--330}, publisher = {mathdoc}, volume = {18}, year = {1979}, zbl = {0424.04001}, url = {http://geodesic.mathdoc.fr/item/SF_1979__18_134362/} }
E.M. Norris. The structure of an idempotent relation.. Semigroup forum, Tome 18 (1979), pp. 319-330. http://geodesic.mathdoc.fr/item/SF_1979__18_134362/