[6] RFC 2534 - Media Features for Display, Print, and Fax, , https://tools.ietf.org/html/rfc2534
[8] RFC 2879 - Content Feature Schema for Internet Fax (V2), , https://tools.ietf.org/html/rfc2879
[15] RFC 4569: Internet Assigned Number Authority (IANA) Registration of the Message Media Feature Tag, , https://www.rfc-editor.org/rfc/rfc4569.html
[4] RFC 2530 - Indicating Supported Media Features Using Extensions to DSN and MDN, , https://tools.ietf.org/html/rfc2530
[5] RFC 2531 - Content Feature Schema for Internet Fax, , https://tools.ietf.org/html/rfc2531
[9] RFC 2938 - Identifying Composite Media Features, , https://tools.ietf.org/html/rfc2938
[10] RFC Errata Report » RFC Editor, https://www.rfc-editor.org/errata_search.php?rfc=2938
[13] RFC 4508: Conveying Feature Tags with the Session Initiation Protocol (SIP) REFER Method, , https://www.rfc-editor.org/rfc/rfc4508.html