Voir la notice de l'article provenant de la source Czech Digital Mathematics Library
@article{MASLO_1966__16_3_a0, author = {Wallace, Alexander Doniphan}, title = {Problems on {Periodicity} - {Functions} and {Semigroups}}, journal = {Mathematica slovaca}, pages = {209--212}, publisher = {mathdoc}, volume = {16}, number = {3}, year = {1966}, mrnumber = {0212774}, zbl = {0152.21501}, language = {en}, url = {http://geodesic.mathdoc.fr/item/MASLO_1966__16_3_a0/} }
Wallace, Alexander Doniphan. Problems on Periodicity - Functions and Semigroups. Mathematica slovaca, Tome 16 (1966) no. 3, pp. 209-212. http://geodesic.mathdoc.fr/item/MASLO_1966__16_3_a0/