Katsaros, Georgios, et al. “Comparison of the Impact of FWM on Binary, Duobinary and Dicode Modulation in DWDM Systems.”10.1109/LEOS.2000.890656__Proceedings of the 2000 IEEE Annual Meeting Conference , vol. 1, IEEE, 2000, pp. 27–28, doi:10.1109/LEOS.2000.890656.