@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/}
}