@article{DE_1976_12_7_a9,
     author = {A. I. Perov and Yu. V. Trubnikov},
     title = {Monotone differential {equations.~II}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1223--1237},
     publisher = {mathdoc},
     volume = {12},
     number = {7},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_7_a9/}
}