@article{DE_1969_5_2_a7,
     author = {\`E. I. Grudo},
     title = {The solutions of a certain equation with periodic coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {296--304},
     publisher = {mathdoc},
     volume = {5},
     number = {2},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1969_5_2_a7/}
}