TY  - DATA
AU  - Olum, Paul.
TI  - Invariants for effective homotopy classification and extension of mappings 
T2  - Memoirs of the American Mathematical Society, 
SN  - 9780821899809 (online)
PY  - 1961///
CY  - Providence, R.I.
PB  - American Mathematical Society
UR  - http://www.ams.org/memo/0037
ER  -