@article{DE_1989_25_6_a24,
     author = {V. A. Lunkevich and K. S. Sibirskii},
     title = {Quadratic zero-systems of differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1056--1058},
     publisher = {mathdoc},
     volume = {25},
     number = {6},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_6_a24/}
}