@article{DE_1986_22_8_a25,
     author = {M. M. Khapaev and V. N. Shinkin},
     title = {Extremal properties of the {Lyapunov} function on unstable resonance regimes in the multifrequency case},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1463--1466},
     publisher = {mathdoc},
     volume = {22},
     number = {8},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_8_a25/}
}