TY  - JOUR
AU  - N. L. Koval'
TI  - On upper and lower approximative liftings
JO  - Trudy Matematicheskogo Instituta imeni V.A. Steklova
PY  - 1985
SP  - 129
EP  - 130
VL  - 40
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/RM_1985_40_6_a11/
LA  - en
ID  - RM_1985_40_6_a11
ER  -