1. Amit, C., Ching, E. S. C., Kadanoff, L. P., and Rom-Kedar, V. (1992). J. Nonlinear Sci.
2, 9.
2. Bender, C. M., et al. (1985). Phys. Rev. Lett.
55, 901.
3. Born, M., and Jordan, P. (1925). Z. Phys.
34, 858.
4. Dirac, P. A. M. (1930). The Principles of Quantum Mechanics. Oxford: Clarendon Press.
5. Gelfreich, V. G., Lazutkin, V. F., and Svanidze, N. V. (1994). Physica
D71, 82.