TY  - JOUR
AU  - Leif Kristensen
TI  - On Secondary Cohomology Operations.
JO  - Mathematica Scandinavica
PY  - 1963
SP  - 57
EP  - 82
VL  - 12
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MS2_1963__12_165835/
ID  - MS2_1963__12_165835
ER  -