%0 Journal Article
%A A. Fraguela Collar
%T On perturbation of a~polyharmonic operator by delta-like potentials
%J Sbornik. Mathematics
%D 1987
%P 389-396
%V 58
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_1987_58_2_a4/
%G en
%F SM_1987_58_2_a4