TY  - JOUR
AU  - M. F. Raţă
TI  - Unsolvability of the problem of functional expressibility in the modal logic $\mathrm{S}4$
JO  - Doklady Akademii Nauk
PY  - 1983
SP  - 814
EP  - 817
VL  - 268
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1983_268_4_a9/
LA  - ru
ID  - DAN_1983_268_4_a9
ER  -