TY  - JOUR
AU  - S. V. Lapin
TI  - Differential perturbations and $D_\infty$-differential modules
JO  - Sbornik. Mathematics
PY  - 2001
SP  - 1639
EP  - 1659
VL  - 192
IS  - 11
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_2001_192_11_a2/
LA  - en
ID  - SM_2001_192_11_a2
ER  -