1. Anderson, J. L., and P. G. Bergmann: Phys. Rev. 83, 1018 (1951)
2. -On the consistency of Dirac's canonical formulation of general relativity. Preprint London 1960
3. -Coordinate conditions and canonical formulations in gravitational theory. Preprint Hoboken Stevens Inst, of Techn. 1963
4. -: Eastern Theor. Phys. Conf., p. 387. New York: Gordon and Breach 1963
5. -: Rev. mod. Phys. 36, 929 (1964)