@article{DE_1968_4_2_a10,
     author = {R. G. Dymanov},
     title = {Singular points for three-dimensional systems of total differential equations in four-dimensional space},
     journal = {Differencialʹnye uravneni\^a},
     pages = {283--289},
     publisher = {mathdoc},
     volume = {4},
     number = {2},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_2_a10/}
}