Noumba Um, P. (2004). A model for calculating interconnection costs in telecommunications. World Bank : PPIAF.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিNoumba Um, Paul. A Model for Calculating Interconnection Costs in Telecommunications. Washington, D.C.: World Bank : PPIAF, 2004.
M.L.A (9 ম সংস্করণ) উদ্ধৃতিNoumba Um, Paul. A Model for Calculating Interconnection Costs in Telecommunications. World Bank : PPIAF, 2004.