Yu.V. Andreyev
Institute of Radio Engineering and Electronics of RAS
Mokhovaya st. 11, GSP-3, Moscow 103907, Russia.
Email: [email protected]
Izv. VUZov, Prikladnaya nelineinaya dinamika, 1995, vol. 3, no. 5, pp. 3-15.
Received Feb. 20 1995, revised Sep. 22 1995.