%0 Journal Article %A V. F. Butuzov %T A singularly perturbed equation of elliptic type with two small parameters %J Differencialʹnye uravneniâ %D 1976 %P 1793-1803 %V 12 %N 10 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1976_12_10_a6/ %G ru %F DE_1976_12_10_a6