@article{DAN_1957_117_1_a9,
     author = {V. A. Yakubovich},
     title = {On a class of non-linear differential equations},
     journal = {Doklady Akademii Nauk},
     pages = {44--46},
     publisher = {mathdoc},
     volume = {117},
     number = {1},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_117_1_a9/}
}