Documents by JM. Valin
2012, RFC6569: Guidelines for Development of an Audio Codec within the IETF
2012, RFC6716: Definition of the Opus Audio Codec
2015, RFC7587: RTP Payload Format for the Opus Speech and Audio Codec
2016, RFC7874: WebRTC Audio Codec and Processing Requirements
2017, RFC8251: Updates to the Opus Audio Codec