@article{DE_1971_7_9_a14,
     author = {P. V. Sokolov},
     title = {Limit theorems on the existence of integral surfaces that are tangent to singular integral elements},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1672--1683},
     publisher = {mathdoc},
     volume = {7},
     number = {9},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_9_a14/}
}