TY  - JOUR
AU  - A. A. Fridman
TI  - Degrees of unsolvability of the word problem for finitely presented groups
JO  - Doklady Akademii Nauk
PY  - 1962
SP  - 805
EP  - 808
VL  - 147
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1962_147_4_a15/
LA  - ru
ID  - DAN_1962_147_4_a15
ER  -