TY  - JOUR
AU  - János Bognár
TI  - Non-negativity properties of operators in spaces with indefinite metric
JO  - Annales Fennici Mathematici
PY  - 1964
VL  - 336-344
UR  - http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1964.336-10/
DO  - 10.5186/aasfm.1964.336-10
LA  - en
ID  - AFM_1964_336-344_a14
ER  -