Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{SF_1977__15_134247, author = {E.M. Norris}, title = {Union preserving homomorphisms of semigroups of closed relations.}, journal = {Semigroup forum}, pages = {169--180}, publisher = {mathdoc}, volume = {15}, year = {1977}, zbl = {0383.20054}, url = {http://geodesic.mathdoc.fr/item/SF_1977__15_134247/} }
E.M. Norris. Union preserving homomorphisms of semigroups of closed relations.. Semigroup forum, Tome 15 (1977), pp. 169-180. http://geodesic.mathdoc.fr/item/SF_1977__15_134247/