@article{GDZPPN002022281,
title = {The Numerical Range of a Continuous Mapping of a Normed Space. (Short Communication).},
journal = {Aequationes mathematicae},
volume = {1},
year = {1968},
pages = {205-205},
zbl = {0162.20101},
url = {http://dml.mathdoc.fr/item/GDZPPN002022281}
}
Bonsall, F.F.; Cain, B.E.; Schneider, H. The Numerical Range of a Continuous Mapping of a Normed Space. (Short Communication).. Aequationes mathematicae, Tome 1 (1968) p. 205. http://gdmltest.u-ga.fr/item/GDZPPN002022281/