@article{DE_1966_2_4_a1,
     author = {V. P. Prokop'ev and S. N. Shimanov},
     title = {On stability in the critical case of a double zero root for systems with an aftereffect},
     journal = {Differencialʹnye uravneni\^a},
     pages = {453--462},
     publisher = {mathdoc},
     volume = {2},
     number = {4},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1966_2_4_a1/}
}