TY  - JOUR
AU  - Barra, G. de
TI  - The boundary of the numerical range
JO  - Glasgow mathematical journal
PY  - 1981
SP  - 69
EP  - 72
VL  - 22
IS  - 1
UR  - http://geodesic.mathdoc.fr/articles/10.1017/S001708950000447X/
DO  - 10.1017/S001708950000447X
ID  - 10_1017_S001708950000447X
ER  -