@article{GDZPPN001253972, title = {Varietes de languages et monoide des parties.}, journal = {Semigroup forum}, volume = {20}, year = {1980}, pages = {11-48}, zbl = {0451.20061}, url = {http://dml.mathdoc.fr/item/GDZPPN001253972} }
Pin, J.E. Varietes de languages et monoide des parties.. Semigroup forum, Tome 20 (1980) pp. 11-48. http://gdmltest.u-ga.fr/item/GDZPPN001253972/