%0 Journal Article %A I. V. Ponomarev %A A. M. Khapaev %T On the variational method for solving the problem of electron-wave interaction %J Differencialʹnye uravneniâ %D 1988 %P 1828-1831 %V 24 %N 10 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1988_24_10_a25/ %G ru %F DE_1988_24_10_a25