TY  - JOUR
AU  - P. R. Popivanov
TI  - The solvability and hypoellipticity of differential equations
JO  - Trudy Matematicheskogo Instituta imeni V.A. Steklova
PY  - 1974
VL  - 29
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/RM_1974_29_1_a23/
LA  - ru
ID  - RM_1974_29_1_a23
ER  -