@article{IVM_1991_1_a4,
     author = {N. M. Isakov and F. {\CYRM}{\cyru}{\cyrk}{\cyra}{\cyrm}{\cyrb}{\cyra}},
     title = {Local approximations of approximately differentiable functions},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {28--32},
     publisher = {mathdoc},
     number = {1},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1991_1_a4/}
}