@article{DE_1980_16_6_a4,
     author = {N. N. Petrov},
     title = {A generalization of the notion of foliation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1032--1036},
     publisher = {mathdoc},
     volume = {16},
     number = {6},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_6_a4/}
}