@article{DE_1976_12_11_a10,
     author = {V. P. Prokop'ev},
     title = {The stability of the unperturbed motion in the critical case of two zero roots and a pair of pure imaginary roots},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2009--2013},
     publisher = {mathdoc},
     volume = {12},
     number = {11},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_11_a10/}
}