TY  - BOOK
AU  - Butzer,Paul L.
TI  - Semi-groups of operators and approximation
U1  - 519.8 BUT B  
PY  - 1967///.
CY  - Berlin : 
PB  - Springer-Verlag, 
KW  - Approximation theory
KW  - Semi-group theory
N1  - Includes index.
ER  -