@article{DE_1968_4_10_a7,
     author = {R. G. Dymanov},
     title = {Singular points for two-dimensional systems of total differential equations in four-dimensional space},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1835--1841},
     publisher = {mathdoc},
     volume = {4},
     number = {10},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_10_a7/}
}