@article{DE_1983_19_5_a2,
     author = {\`E. I. Grudo},
     title = {On the theory of stability of ordinary differential systems and {Pfaffian} systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {782--789},
     year = {1983},
     volume = {19},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1983_19_5_a2/}
}