@article{VMUMM_2009_1_a10,
     author = {V. I. Kalenova and V. M. Morozov and P. M. Sobolevskii},
     title = {A study of linear time-varying systems},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {50--60},
     publisher = {mathdoc},
     number = {1},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2009_1_a10/}
}