Quaternions, Torsion and the Physical Vacuum: Theories of M. Sachs and G. Shipov Compared

Cyganski, D., & Page, W. S. (2002). Quaternions, Torsion and the Physical Vacuum: Theories of M. Sachs and G. Shipov Compared. In Gravitation and Cosmology: From the Hubble Radius to the Planck Scale (pp. 499–506). Springer Netherlands. https://doi.org/10.1007/0-306-48052-2_51