Quasi-periodic oscillations in a network of four Rossler chaotic   oscillators
  We consider a network of four non-identical chaotic Rossler oscillators. The possibility is shown of appearance of two-, three- and four-frequency invariant tori resulting from secondary quasi-periodic Hopf bifurcations and saddle-node homoclinic bifurcations of tori. 
Alexander P. Kuznetsov, Igor R. Sataev, Yuliya V. Sedova and Ludmila   V. Turukina
nlin.CD