@article{ZNSL_1972_27_a14,
     author = {V. A. Yakubovich},
     title = {A~theorem on the stability of a~linear hamiltonian system with periodic coefficients},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {220--234},
     publisher = {mathdoc},
     volume = {27},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1972_27_a14/}
}