Florian Hammer Peter Reichl Thomas Ziegler Where packet traces meet speech samples: an instrumental approach to perceptual QoS evaluation of VoIP. 273-280 2004 conf/iwqos/2004 IWQoS http://dx.doi.org/10.1109/IWQOS.2004.1309393 db/conf/iwqos/iwqos2004.html#HammerRZ04