%0 Journal Article
%A Barra, G. de
%T The boundary of the numerical range
%J Glasgow mathematical journal
%D 1981
%P 69-72
%V 22
%N 1
%U http://geodesic.mathdoc.fr/articles/10.1017/S001708950000447X/
%R 10.1017/S001708950000447X
%F 10_1017_S001708950000447X