%0 Journal Article
%A Kreith, Kurt
%T Lower Bounds for the Essential Spectrum of Fourth-Order Differential Operators
%J Canadian journal of mathematics
%D 1969
%P 460-465
%V 21
%N 1
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1969-050-6/
%R 10.4153/CJM-1969-050-6
%F 10_4153_CJM_1969_050_6