@article{ZVMMF_1992_32_4_a13,
     author = {A. M. Bagirov},
     title = {A method of approximating a subdifferential},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {652--658},
     publisher = {mathdoc},
     volume = {32},
     number = {4},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1992_32_4_a13/}
}