TY  - JOUR
AU  - Yu. V. Egorov
AU  - P. R. Popivanov
TI  - A class of pseudodifferential equations of principal type having no solutions
JO  - Doklady Akademii Nauk
PY  - 1973
SP  - 775
EP  - 777
VL  - 209
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1973_209_4_a4/
LA  - ru
ID  - DAN_1973_209_4_a4
ER  -