@article{DE_1975_11_4_a21,
     author = {S. K. Norkin},
     title = {Uniqueness of the $O$-curve along a direction that is analogous to the exceptional one},
     journal = {Differencialʹnye uravneni\^a},
     pages = {758--759},
     publisher = {mathdoc},
     volume = {11},
     number = {4},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_4_a21/}
}