Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1991_318_4_a5, author = {Yu. L. Ershov}, title = {Projective $\Gamma$-groups}, journal = {Doklady Akademii Nauk}, pages = {798--801}, publisher = {mathdoc}, volume = {318}, number = {4}, year = {1991}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1991_318_4_a5/} }
Yu. L. Ershov. Projective $\Gamma$-groups. Doklady Akademii Nauk, Tome 318 (1991) no. 4, pp. 798-801. http://geodesic.mathdoc.fr/item/DAN_1991_318_4_a5/