TY  - BOOK
AU  - Butzer,Paul Leo
AU  - Berens,Hubert
TI  - Semi-groups of operators and approximation
PY  - 1967///
CY  - New York
PB  - Springer-Verlag
KW  -  Banach spaces
KW  -  Semigroups
KW  -  Approximation theory
KW  -  Integrals
ER  -