@article{DE_1975_11_10_a10,
     author = {A. A. Reinfeld},
     title = {The reduction theorem for closed trajectories},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1811--1818},
     publisher = {mathdoc},
     volume = {11},
     number = {10},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_10_a10/}
}