TY  - JOUR
AU  - M. M. Kipnis
TI  - Invariant properties of systems of formulas of elementary axiomatic

JO  - Izvestiya. Mathematics 
PY  - 1970
SP  - 965
EP  - 978
VL  - 4
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1970_4_5_a0/
LA  - en
ID  - IM2_1970_4_5_a0
ER  -