1. Aldersley, S. J. (1976). ?The Einstein-Cartan Theory and the Role of Torsion in Gravitation,? Master's Thesis (unpublished). Department of Applied Mathematics, University of Waterloo.
2. Aldersley, S. J. (1977).Phys. Rev. D.,15, 370.
3. Hehl, F. W. (1973).Gen. Rel. Grav.,4, 333.
4. Hehl, F. W. (1974).Gen. Rel. Grav.,5, 491.
5. Horndeski, G. W. (1976).Utilitas Mathematica,9, 3.