Hellmann, Frank Quantum Gravity & Unified Theories, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;
1207.4596 (Preprint), 569KB
sigma13-008.pdf (Any fulltext), 532KB
Bianchi, E., & Hellmann, F. (2013). The Construction of Spin Foam Vertex Amplitudes. Symmetry, Integrability and Geometry: Methods and Applications (SIGMA), 9: 008. doi:10.3842/SIGMA.2013.008.