@article{DE_1969_5_6_a13,
     author = {L. M. Vaserman and A. Ya. Lepin},
     title = {Generalized {Bern{\v} s}te{\v\i}n conditions for nonlinear systems of ordinary differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1107--1113},
     publisher = {mathdoc},
     volume = {5},
     number = {6},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1969_5_6_a13/}
}