1. C. F. F. Karney,Physica 8D:360 (1983).
2. B. V. Chirikov, Lecture Notes in Physics No. 179 (Springer, Berlin, 1983), p. 29.
3. J. D. Meiss, J. R. Cary, C. Grebogi, J. D. Crawford, A. N. Kaufrnan, and H. D. I. Abarbanel,Physica 6D:375 (1983).
4. R. S. MacKay, Ph.D. thesis, Princeton University, 1982 (University Microfilms, Ann Arbor, Michigan).
5. R. S. MacKay, J. D. Meiss, and I. C. Percival,Phys. Rev. Lett. 52:697 (1984); andPhysica 13D:55 (1984).