%0 Journal Article
%A Ian Knowles
%T On the Existence of Minimal Operators for Schrödinger-Type Differential Expressions.
%J Mathematische Annalen
%D 1978
%P 221-228
%V 233
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MAN_1978__233_163109/
%F MAN_1978__233_163109