Voir la notice de l'article provenant de la source Czech Digital Mathematics Library
@article{MASLO_1991__41_1_a5, author = {Chajda, Ivan}, title = {Every at most four element algebra has a {Mal'cev} theory for permutability}, journal = {Mathematica slovaca}, pages = {35--39}, publisher = {mathdoc}, volume = {41}, number = {1}, year = {1991}, mrnumber = {1094982}, zbl = {0779.08001}, language = {en}, url = {http://geodesic.mathdoc.fr/item/MASLO_1991__41_1_a5/} }
Chajda, Ivan. Every at most four element algebra has a Mal'cev theory for permutability. Mathematica slovaca, Tome 41 (1991) no. 1, pp. 35-39. http://geodesic.mathdoc.fr/item/MASLO_1991__41_1_a5/