Yu, W., Chen, G., Cao, M., Kurths, J. (2010): Second-order consensus for multiagent systems with directed topologies and nonlinear dynamics. - IEEE Transactions on Systems, Man, and Cybernetics - Part B: Cybernetics, 40, 3, 881-891.https://doi.org/10.1109/TSMCB.2009.2031624