Andrey I. Panas*, Tao Yang** and Leon O. Chua**
*)Institute of Radioengineering and Electronics of the Russian Academy of Sciences
Mokhovaya st., 11, Moscow, 103907, Russia
International Journal of Bifurcations and Chaos,
1998, vol. 8, No. 3, pp. 639-644
Received October 30, 1997. Revised December 31, 1997.