Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{PORMA_1959__18_4_114826, author = {Conrad, Paul}, title = {Semigroups of real numbers}, journal = {Portugaliae mathematica}, pages = {199--201}, publisher = {mathdoc}, volume = {18}, number = {4}, year = {1959}, mrnumber = {0125167}, zbl = {0098.01702}, language = {en}, url = {http://geodesic.mathdoc.fr/item/PORMA_1959__18_4_114826/} }
Conrad, Paul. Semigroups of real numbers. Portugaliae mathematica, Tome 18 (1959) no. 4, pp. 199-201. http://geodesic.mathdoc.fr/item/PORMA_1959__18_4_114826/