@misc{VMUMM_1991_2_a20,
     title = {Lomonosov proceedings (april 1990)},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {90--101},
     publisher = {mathdoc},
     number = {2},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1991_2_a20/}
}