TY  - JOUR
AU  - Yu. I. Merzlyakov
TI  - Positive formulae on free groups
JO  - Algebra i logika
PY  - 1966
SP  - 25
EP  - 42
VL  - 5
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/AL_1966_5_4_a2/
LA  - ru
ID  - AL_1966_5_4_a2
ER  -