@article{DE_1987_23_5_a22,
     author = {V. N. Gorbuzov and {\CYRS}. {\CYRI}. Kishkel},
     title = {Apropos a theorem of {Wittich}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {891--893},
     publisher = {mathdoc},
     volume = {23},
     number = {5},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1987_23_5_a22/}
}