%0 Journal Article %A A. M. Abdrakhmanov %T Elliptic systems that are degenerate at a point %J Differencialʹnye uravneniâ %D 1977 %P 276-284 %V 13 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1977_13_2_a5/ %G ru %F DE_1977_13_2_a5