%0 Journal Article %A V. A. Dzhrbashyan %T On essential positivity of electron energies in relativistic theory. Realistic %J Doklady Akademii Nauk %D 1991 %P 897-899 %V 316 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1991_316_4_a30/ %G ru %F DAN_1991_316_4_a30