Hardy, W. C. (2003). VoIP Service qualityMeasuring and evaluating packet-switched voiceWilliam C. Hardy. McGraw-Hill.
Čikaški stil citiranja (17. izdanje)Hardy, William C. VoIP Service QualityMeasuring and Evaluating Packet-switched VoiceWilliam C. Hardy. McGraw-Hill, 2003.
MLA način citiranja (8. izdanje)Hardy, William C. VoIP Service QualityMeasuring and Evaluating Packet-switched VoiceWilliam C. Hardy. McGraw-Hill, 2003.
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