TY  - JOUR
AU  - V. V. Gorbatsevich
TI  - Letter to the editors
JO  - Izvestiya. Mathematics 
PY  - 2020
SP  - 1250
VL  - 84
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_2020_84_6_a6/
LA  - en
ID  - IM2_2020_84_6_a6
ER  -