%0 Journal Article %A F. G. Avkhadiev %T Singular cases of the principle of correspondence of boundaries %J Trudy seminara po kraevym zadačam %D 1976 %P 13-23 %V 13 %N 13 %I mathdoc %U http://geodesic.mathdoc.fr/item/KUKZ_1976_13_13_a1/ %G ru %F KUKZ_1976_13_13_a1