%0 Journal Article %A V. R. Vinokurov %T Letter to the editors %J Differencialʹnye uravneniâ %D 1970 %P 1532 %V 6 %N 8 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1970_6_8_a28/ %G ru %F DE_1970_6_8_a28