%0 Journal Article %A M. A. Shubin %T The Favard--Muhamadiev theory and pseudo-differential operators %J Doklady Akademii Nauk %D 1975 %P 1278-1280 %V 225 %N 6 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1975_225_6_a10/ %G ru %F DAN_1975_225_6_a10