@article{DE_1976_12_9_a19,
     author = {V. N. Laptinskii},
     title = {A study of the stability of linear periodic differential systems by the method of variation of a parameter},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1715--1718},
     publisher = {mathdoc},
     volume = {12},
     number = {9},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_9_a19/}
}