TY  - JOUR
AU  - Daniele Morbidelli
TI  - Fractional Sobolev norms and structure of Carnot-Carathéodory balls for Hörmander vector fields
JO  - Studia Mathematica
PY  - 2000
SP  - 213
EP  - 244
VL  - 139
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/sm-139-3-213-244/
DO  - 10.4064/sm-139-3-213-244
LA  - fr
ID  - 10_4064_sm_139_3_213_244
ER  -