Noumba Um, P. (2004). A model for calculating interconnection costs in telecommunications. World Bank : PPIAF.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNoumba Um, Paul. A Model for Calculating Interconnection Costs in Telecommunications. Washington, D.C.: World Bank : PPIAF, 2004.
एमएलए (9वां संस्करण) प्रशस्ति पत्रNoumba Um, Paul. A Model for Calculating Interconnection Costs in Telecommunications. World Bank : PPIAF, 2004.