%0 Journal Article %A Yu. G. Shondin %T Perturbation of differential operators on high-codimension manifold and the extension theory for symmetric linear relations in an indefinite metric space %J Teoretičeskaâ i matematičeskaâ fizika %D 1992 %P 466-472 %V 92 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/TMF_1992_92_3_a8/ %G en %F TMF_1992_92_3_a8