@article{DE_1972_8_6_a24,
     author = {V. V. Nikonenko},
     title = {The existence and uniqueness of $O$-curves in normal domains},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1126--1129},
     year = {1972},
     volume = {8},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1972_8_6_a24/}
}