1. Finkelstein, D., and Misner, C. W. (1959). Ann. Phys. (NY )
6, 230.
2. Gibbons, G. W., and Hawking, S. W. (1992). Phys. Rev. Lett.
69, 1719.
3. Finkelstein, D., and McCollum, G. (1975). J. Math. Phys.
16, 2250.
4. Finkelstein, D. (1993). In Directions in General Relativity, Proceedings of the 1993 International Symposium in Maryland, Volume 1: Papers in honor of C. W. Misner, B. L. Hu, M. P. Ryan Jr., and C. V. Vishveshwara, eds. (Cambridge University Press, Cambridge), pp. 99–103.
5. Dunn, K. A., Harriott, T. A., and Williams, J. G. (1996). J. Math. Phys.
37, 5637.