Voir la notice de l'article provenant de la source Math-Net.Ru
@article{TRSPY_1983_154_a30, author = {H. Zieschang}, title = {Subgroups of a~free product of cyclic groups}, journal = {Informatics and Automation}, pages = {284--295}, publisher = {mathdoc}, volume = {154}, year = {1983}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/TRSPY_1983_154_a30/} }
H. Zieschang. Subgroups of a~free product of cyclic groups. Informatics and Automation, Topology, Tome 154 (1983), pp. 284-295. http://geodesic.mathdoc.fr/item/TRSPY_1983_154_a30/