1. Alvarez-Gaumé, L., Witten, E.: Gravitational anomalies. Nucl. Phys.B 234, 269 (1983)
2. Atiyah, M. F., Singer, I. M.: Ann. Math.93, 119 (1971)
3. Atiyah, M. F., Singer, I. M.: Dirac operators to vector potentials. Proc. Natl. Acad. Sci.81, 2597 (1984)
4. Alvarez-Gaumé, L., Ginsparg, P.: The topological meaning of non-Abelian anomalies. Harvard Preprint HUTP-83/A018 (1983)
5. Lott, J.: Harvard Mathematics Preprint (1984)