%0 Journal Article %A V. V. Sobolev %T The relationship between emissivity and absorptivity of media %J Doklady Akademii Nauk %D 1973 %P 1071-1073 %V 209 %N 5 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1973_209_5_a19/ %G ru %F DAN_1973_209_5_a19