The Numerical Range of a Continuous Mapping of a Normed Space F.F. BONSALL; B.E. CAIN; H. SCHNEIDER — 1969 Aequationes mathematicae
The Numerical Range of a Continuous Mapping of a Normed Space. (Short Communication). F.F. Bonsall; B.E. Cain; H. Schneider — 1968 Aequationes mathematicae
Extreme Positive Operators on Algebras of Functions. J. Lindenstrauss; F.F. Bonsall; R. R. Phelps — 1966 Mathematica Scandinavica