1. J Buck and E Buck, Science 159, 1319 (1968) J Buck and E Buck, Sci. Am. 234, 74 (1976)
2. S Yamaguchi, H Isejima, T Matsuo, R Okura, K Yagita, M Kobayashi and H Okamura, Science 302, 1408 (2003)
3. I Z Kiss, Y Zhai and J L Hudson, Science 296, 1676 (2002)
4. K Wiesenfeld and J W Swift, Phys. Rev . E51, 1020 (1995)
5. P Tass, Phys. Rev . E56, 2043 (1997) A Pikovsky, M Rosenblum and J Kurths, Synchronization, in: A univ ersal concept in nonlinear science (Cambridge University Press, Cambridge, 2001)