Bojovic, Z., Z. Peric, V. Delic, E. Secerov, M. Secujski, and V. Senk. “Comparative Analysis of the Performance of Different Codecs in a Live VoIP Network Using SIP Protocol”. Elektronika Ir Elektrotechnika, vol. 117, no. 1, Jan. 2012, pp. 37-42, doi:10.5755/j01.eee.117.1.1050.