1. T. A. Brody, J. Flores, J. B. French, P. A. Mello A. Pandeyc and S. S. M. Wong, Rev. Mod. Phys., 53:385 (1981).
2. C. E. Porter, Statistical Theories of Spectra: Fluctuations, Acad., New York (1965).
3. S. S. M. Wong, in this volume.
4. O. Bohigas, M. J. Giannoni and C. Schmit, in this volume.
5. M. V. Berry, Lectures given at Les Houches Summer School 1981 ( North Holland) and references therein.