Phase-lag synchronization analysis in complex systems with directed inter-relations V.S.G. Martins, A.C. Rodrigues, H.A. Cerdeira and B.S. Machado Eur. Phys. J. Special Topics, 225 1 (2016) 41-49 Published online: 29 February 2016 DOI: 10.1140/epjst/e2016-02618-7