1. Weyl, H.: Space-Time-Matter. Dover (1952)
2. Xin, Y.: General Relativity on Spinor-Tensor Manifold. In: Bergman, P.G., de.Sabbata, V., Treder, H.J. (eds.) Quantum Gravity - Int. School on Cosmology & Gravitation, XIV Course, pp 382–411. World Scientific (1996)
3. Cirilo-Lombardo, D.J.: Int. J. Theor. Phys. 49, 1288 (2010)
4. Cirilo-Lombardo, D.J.: Int. J. Theor. Phys. 50, 1699 (2011)
5. Cirilo-Lombardo, D.J.: Int. J. Theor. Phys. 50, 3621 (2011)