TY  - JOUR
AU  - V. Yu. Shavrukov
TI  - On two extensions of the logic of provability~GL
JO  - Sbornik. Mathematics
PY  - 1991
SP  - 255
EP  - 270
VL  - 69
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1991_69_1_a14/
LA  - en
ID  - SM_1991_69_1_a14
ER  -