Volpato, Roberto Quantum Gravity & Unified Theories, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;
1312.0622.pdf (Preprint), 2MB
Persson, D., & Volpato, R. (2014). Second Quantized Mathieu Moonshine. Communications in Number Theory and Physics, 8(3), 403-509. doi:10.4310/CNTP.2014.v8.n3.a2.