TY  - JOUR
AU  - Bethuel, F.
TI  - A characterization of maps in $H^1 (B^3, S^2)$ which can be approximated by smooth maps
JO  - Annales de l'I.H.P. Analyse non linéaire
PY  - 1990
SP  - 269
EP  - 286
VL  - 7
IS  - 4
PB  - Gauthier-Villars
UR  - http://www.numdam.org/item/AIHPC_1990__7_4_269_0/
LA  - en
ID  - AIHPC_1990__7_4_269_0
ER  -