@article{DE_1981_17_3_a0,
     author = {\`E. I. Grudo and L. A. Poplavskaya},
     title = {The structure of the solutions of a two-dimensional periodic differential {system.~II}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {395--410},
     publisher = {mathdoc},
     volume = {17},
     number = {3},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1981_17_3_a0/}
}