Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{PORMA_1959__18_2_114815, author = {Kleinfeld, Erwin}, title = {Rings of $(\gamma ,\delta )$ type}, journal = {Portugaliae mathematica}, pages = {107--110}, publisher = {mathdoc}, volume = {18}, number = {2}, year = {1959}, mrnumber = {0110738}, zbl = {0090.02402}, language = {en}, url = {http://geodesic.mathdoc.fr/item/PORMA_1959__18_2_114815/} }
Kleinfeld, Erwin. Rings of $(\gamma ,\delta )$ type. Portugaliae mathematica, Tome 18 (1959) no. 2, pp. 107-110. http://geodesic.mathdoc.fr/item/PORMA_1959__18_2_114815/