1. Vishveshwara, C. V., Phys. Rev. (1970, in the press).
2. Regge, T., and Wheeler, J. A., Phys. Rev., 108, 1903 (1957).
3. Edelstein, L. A., and Vishveshwara, C. V., Phys. Rev. (1970, in the press).
4. Edelstein, L. A., thesis, University of Maryland (1970).