TY  - JOUR
TI  - Joint sessions of the Petrovskii Seminar on differential equations and mathematical problems of physics and of the Moscow Mathematical Society (twelfth meeting, 18--21 January~1989)
JO  - Trudy Matematicheskogo Instituta imeni V.A. Steklova
PY  - 1989
SP  - 173
EP  - 202
VL  - 44
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/RM_1989_44_4_a5/
LA  - en
ID  - RM_1989_44_4_a5
ER  -