Sjoberg, J., Westerlund, M., Lakaniemi, A., and S. Wenger, "RTP Payload Format for the Extended Adaptive Multi-Rate Wideband (AMR-WB+) Audio Codec", RFC 4352, DOI 10.17487/RFC4352, January 2006, <https://www.rfc-editor.org/info/rfc4352>.