Voir la notice de l'article provenant de la source Math-Net.Ru
@article{IVM_1983_3_a14, author = {Sh. T. Ishmukhametov}, title = {Index sets of difference classes}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {78--79}, publisher = {mathdoc}, number = {3}, year = {1983}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1983_3_a14/} }
Sh. T. Ishmukhametov. Index sets of difference classes. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 3 (1983), pp. 78-79. http://geodesic.mathdoc.fr/item/IVM_1983_3_a14/