TY  - JOUR
AU  - Hsiang, Fu Cheng
TI  - On a theorem of Burkill-Petersen
JO  - Portugaliae mathematica
PY  - 1963
SP  - 137
EP  - 141
VL  - 22
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/PORMA_1963__22_3_114902/
LA  - en
ID  - PORMA_1963__22_3_114902
ER  -