TY  - DATA
AU  - Peter Gabriel; M. Zisman
TI  - Calculus of Fractions and Homotopy Theory
SN  - 9783642858444
PY  - 1967///
PB  - Springer Berlin Heidelberg
KW  - Mathematics and Statistics
UR  - https://doi.org/10.1007/978-3-642-85844-4
ER  -