Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{SF_1978__16_134292, author = {N. Knox}, title = {The inverse hull of the free semigroup on a set {X.}}, journal = {Semigroup forum}, pages = {345--354}, publisher = {mathdoc}, volume = {16}, year = {1978}, zbl = {0407.20047}, url = {http://geodesic.mathdoc.fr/item/SF_1978__16_134292/} }
N. Knox. The inverse hull of the free semigroup on a set X.. Semigroup forum, Tome 16 (1978), pp. 345-354. http://geodesic.mathdoc.fr/item/SF_1978__16_134292/