Voir la notice de l'article provenant de la source Mathematicac Balkanica website
@article{MABA_1991_5_3_a3, author = {Shi Mingquan}, title = {\ensuremath{\pi}1-Semigroup}, journal = {Mathematica balkanica}, pages = {203}, publisher = {mathdoc}, volume = {5}, number = {3}, year = {1991}, url = {http://geodesic.mathdoc.fr/item/MABA_1991_5_3_a3/} }
Shi Mingquan. π1-Semigroup. Mathematica balkanica, Tome 5 (1991) no. 3, p. 203. http://geodesic.mathdoc.fr/item/MABA_1991_5_3_a3/