Noumba Um, P. (2004). A model for calculating interconnection costs in telecommunications. World Bank : PPIAF.
Cytowanie według stylu Chicago (wyd. 17)Noumba Um, Paul. A Model for Calculating Interconnection Costs in Telecommunications. Washington, D.C.: World Bank : PPIAF, 2004.
Cytowanie według stylu MLA (wyd. 9)Noumba Um, Paul. A Model for Calculating Interconnection Costs in Telecommunications. World Bank : PPIAF, 2004.