TY  - JOUR
AU  - Hu, Sze-Tsen
TI  - An axiomatic approach to homotopy theory without using the relative groups
JO  - Portugaliae mathematica
PY  - 1961
SP  - 95
EP  - 103
VL  - 20
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/PORMA_1961__20_2_114855/
LA  - en
ID  - PORMA_1961__20_2_114855
ER  -