@article{ZVMMF_1992_32_7_a2,
     author = {A. B. Vasil'eva and M. A. Petrova},
     title = {Contrast structures in equations of elliptic type},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {1007--1015},
     publisher = {mathdoc},
     volume = {32},
     number = {7},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1992_32_7_a2/}
}