@article{DE_1965_1_12_a6,
     author = {V. I. Zhukovskii},
     title = {Instability and conditional stability in the critical case of $n$ zero roots},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1601--1605},
     publisher = {mathdoc},
     volume = {1},
     number = {12},
     year = {1965},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1965_1_12_a6/}
}