Generalized Phase Synchronization in unidirectionally coupled chaotic   oscillators
  We investigate phase synchronization between two identical or detuned response oscillators coupled to a slightly different drive oscillator. Our result is that phase synchronization can occur between response oscillators when they are driven by correlated (but not identical) inputs from the drive oscillator. We call this phenomenon Generalized Phase Synchronization (GPS) and clarify its characteristics using Lyapunov exponents and phase difference plots. 
Dae-Sic Lee, Won-Ho Kye, Sunghwan Rim, Tae-Yoon Kwon, and Chil-Min Kim