TY  - JOUR
TI  - Joint sessions of the Petrovskii Seminar on differential equations and mathematical problems of physics and the Moscow Mathematical Society (Thirteenth session, 2--5 February~1990)
JO  - Trudy Matematicheskogo Instituta imeni V.A. Steklova
PY  - 1990
SP  - 127
EP  - 155
VL  - 45
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/RM_1990_45_4_a2/
LA  - en
ID  - RM_1990_45_4_a2
ER  -