1. The Topology of Fibre Bundles;Steenrod,1999
2. Characteristic classes, Annals of Mathematics Studies;Milnor,1974
3. Fibre bundles;Husemoller,1994
4. Global anomalies, string theory and spacetime topology;Killingback;Classical Quantum Gravity,1988
5. What is an elliptic object?;Stolz,2004