@article{IVM_1965_5_a14,
     author = {R. M. Nasyrov},
     title = {Stability on a~finite time interval in the case of two pairs of pure imaginary roots},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {115--123},
     year = {1965},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1965_5_a14/}
}