@article{DE_1968_4_9_a4,
     author = {\`E. B. Lebedeva and S. N. Shimanov},
     title = {On the theory of linear equations with periodic coefficients, close to constants, and with lag},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1598--1607},
     publisher = {mathdoc},
     volume = {4},
     number = {9},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_9_a4/}
}