Voir la notice de l'article provenant de la source Czech Digital Mathematics Library
@article{ARM_1981__17_1_a6, author = {Skula, Ladislav}, title = {On $\delta n$-semigroups}, journal = {Archivum mathematicum}, pages = {43--52}, publisher = {mathdoc}, volume = {17}, number = {1}, year = {1981}, mrnumber = {672487}, zbl = {0494.20036}, language = {en}, url = {http://geodesic.mathdoc.fr/item/ARM_1981__17_1_a6/} }
Skula, Ladislav. On $\delta n$-semigroups. Archivum mathematicum, Tome 17 (1981) no. 1, pp. 43-52. http://geodesic.mathdoc.fr/item/ARM_1981__17_1_a6/