TY  - JOUR
AU  - J. Sjöstrand
AU  - J.J. Duistermaat
TI  - A Global Construction for Pseudo-Differential Operators with Non-Involutive Characteristcs.
JO  - Inventiones mathematicae
PY  - 1973
SP  - 209
EP  - 226
VL  - 20
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM_1973__20_142214/
ID  - IM_1973__20_142214
ER  -