Voir la notice de l'article provenant de la source Math-Net.Ru
@article{IVM_1962_5_a11, author = {P. V. Stender}, title = {On primitive elements in a free group of rank $2$}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {101--106}, publisher = {mathdoc}, number = {5}, year = {1962}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1962_5_a11/} }
P. V. Stender. On primitive elements in a free group of rank $2$. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 5 (1962), pp. 101-106. http://geodesic.mathdoc.fr/item/IVM_1962_5_a11/