Kleinschmidt, Axel Quantum Gravity and Unified Theories, AEI Golm, MPI for Gravitational Physics, Max Planck Society;
2012.09198.pdf (Preprint), 701KB
D'Hoker, E., Kleinschmidt, A., & Schlotterer, O. (in preparation). Elliptic modular graph forms I: Identities and generating series.