%0 Journal Article %A V. V. Mityushev %T A functional equation for harmonic functions in a multiply connected domain %J Differencialʹnye uravneniâ %D 1990 %P 2176-2178 %V 26 %N 12 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1990_26_12_a22/ %G ru %F DE_1990_26_12_a22