TY  - BOOK
AU  - Duncan, J
AU  - Bonsall, F F
TI  - Numerical Ranges of Operators on Normed Spaces and of Elements of Normed Algebras
SN  - 0521079888
U1  - 517.5 
PY  - 1971///
CY  - Cambridge
PB  - Cambridge University Press
KW  - Mathematics
ER  -