Voir la notice de l'article provenant de la source Czech Digital Mathematics Library
@article{MASLO_1982__32_3_a10, author = {\v{S}ulka, Robert}, title = {The minimal right $A$-ideal of the free semigroup on a countable set}, journal = {Mathematica slovaca}, pages = {301--304}, publisher = {mathdoc}, volume = {32}, number = {3}, year = {1982}, mrnumber = {670007}, zbl = {0493.20045}, language = {en}, url = {http://geodesic.mathdoc.fr/item/MASLO_1982__32_3_a10/} }
Šulka, Robert. The minimal right $A$-ideal of the free semigroup on a countable set. Mathematica slovaca, Tome 32 (1982) no. 3, pp. 301-304. http://geodesic.mathdoc.fr/item/MASLO_1982__32_3_a10/