@article{AM2_1968__1_135963,
     author = {F.F. Bonsall and B.E. Cain and H. Schneider},
     title = {The {Numerical} {Range} of a {Continuous} {Mapping} of a {Normed} {Space.} {(Short} {Communication).}},
     journal = {Aequationes mathematicae},
     pages = {205--205},
     publisher = {mathdoc},
     volume = {1},
     year = {1968},
     zbl = {0162.20101},
     url = {http://geodesic.mathdoc.fr/item/AM2_1968__1_135963/}
}