1. C. W. Misner, K. S. Thorne, and J. A. Wheeler, Gravitation (Freeman, San Francisco, 1973).
2. L. H. Ryder, Quantum Field Theory (Cambridge University Press, Cambridge, 1987).
3. G. Hunter and R. P. L. Wadlinger, Phys. Essays 2(2), 158 (1989).
4. H. Yilmaz, Annals N. Y Acad Sci.
755, 476 (1995), Wheeler Honorarium.
5. C. O. Alley, Annals N. Y Acad Sci.
755, 464 (1995), Wheeler Honorarium.