@article{DE_1999_35_12_a14,
     author = {V. V. Filippov},
     title = {A mixture of the {Leray--Schauder} and the {Poincar\'e--Andronov} methods in the problem of periodic solutions of ordinary differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1709--1711},
     publisher = {mathdoc},
     volume = {35},
     number = {12},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1999_35_12_a14/}
}