TY  - JOUR
AU  - Kratz, Werner
TI  - Quadratic functionals: positivity, oscillation, Rayleigh's principle
JO  - Archivum mathematicum
PY  - 1998
SP  - 143
EP  - 151
VL  - 34
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/ARM_1998__34_1_a13/
LA  - en
ID  - ARM_1998__34_1_a13
ER  -