1.2.1 Normative References
We conduct frequent surveys of the normative references to assure their continued availability. If you have any issue with finding a normative reference, please contact firstname.lastname@example.org. We will assist you in finding the relevant information.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997, http://www.rfc-editor.org/rfc/rfc2119.txt
[W3C-TTML-1.0] World Wide Web Consortium, "Timed Text Markup Language (TTML) 1.0", W3C Recommendation 18 November 2010, http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/