@article{DE_1970_6_6_a7,
     author = {L. S. Lavrinovich},
     title = {A certain class of systems of two differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1017--1025},
     publisher = {mathdoc},
     volume = {6},
     number = {6},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1970_6_6_a7/}
}