Nicolai, Hermann Quantum Gravity & Unified Theories, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;
351304.pdf (Publisher version), 392KB
De Wit, B., & Nicolai, H. (1985). Hidden symmetry in d = 11 supergravity. Physics Letters B, 155(1-2), 47-53. doi:10.1016/0370-2693(85)91030-5.