TY  - JOUR
AU  - Yang, Zi-Xiao
AU  - Li, Bu-Xi
TI  - On restricted derivative approximation
JO  - Compositio Mathematica
PY  - 1990
SP  - 327
EP  - 331
VL  - 74
IS  - 3
PB  - Kluwer Academic Publishers
UR  - http://www.numdam.org/item/CM_1990__74_3_327_0/
LA  - en
ID  - CM_1990__74_3_327_0
ER  -