TY  - JOUR
AU  - Karel Leeuw
TI  - On the Adjoint Semigroup and Some Problems in the Theory of Approximation.
JO  - Mathematische Zeitschrift
PY  - 1960
SP  - 219
EP  - 234
VL  - 73
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZ_1960__73_169842/
ID  - MZ_1960__73_169842
ER  -