@article{DE_1971_7_7_a5,
     author = {V. A. Pliss},
     title = {The position of the separatrices of saddle-point periodic motions of systems of second order differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1199--1225},
     publisher = {mathdoc},
     volume = {7},
     number = {7},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_7_a5/}
}