S. Sarmiento, J. A. Altabas, D. Izquierdo, I. Garces, S. Spadaro, J. A. Lazaro, “Cost-effective DWDM ROADM Design for Flexible Sustainable Optical Metro-Access Networks”, IEEE/OSA Journal on Optical Communications and Networking, Vol. 9, nº. 12, pp. 1116-1124, 2017.