@article{DE_1994_30_9_a8,
     author = {E. L. Perchik},
     title = {On a remark of {E.} {Goursat} and its applications},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1561--1565},
     year = {1994},
     volume = {30},
     number = {9},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1994_30_9_a8/}
}