%0 Journal Article
%A A. Torgašev
%T Certain notes on the numerical range of an unbounded operator
%J Matematički vesnik
%D 1975
%P 189 
%V 27
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MV_1975_27_1_a24/
%F MV_1975_27_1_a24