Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{SF_1980__20_134411, author = {H. L\"anger}, title = {The free algebra in the variety generated by quasi-trivial semigroups}, journal = {Semigroup forum}, pages = {151--156}, publisher = {mathdoc}, volume = {20}, year = {1980}, zbl = {0441.20038}, url = {http://geodesic.mathdoc.fr/item/SF_1980__20_134411/} }
H. Länger. The free algebra in the variety generated by quasi-trivial semigroups. Semigroup forum, Tome 20 (1980), pp. 151-156. http://geodesic.mathdoc.fr/item/SF_1980__20_134411/