Multiplexing.

Communication networking : an analytical approach by: Kumar, Anurag; Kuri, Joy; Manjunath, D. (Language materials, printed)

Optical WDM Networks : concepts and design principles by: Zheng, Jun; Mouftah, Hussein T. (Language materials, printed)

DWDM : networks, devices, and technology by: Kartalopoulos, Stamatios V. (Language materials, printed)