TY  - JOUR
AU  - J.J. Duistermaat
AU  - V.W. Guillemin
TI  - The Spectrum of Positive Elliptic Operators and Periodic Bicharacteristics.
JO  - Inventiones mathematicae
PY  - 1975
SP  - 39
EP  - 80
VL  - 29
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM_1975__29_142329/
ID  - IM_1975__29_142329
ER  -