1.2 Normative References reads in part:

"S. Bradner, Key words for use in RFCs to Indicate Requirement Levels, http://www.ietf.org/rfc/rfc2119.txt, March 1997"

The citation is incorrect.

Correct citation reads:

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. http://www.ietf.org/rfc/rfc2119.txt

The URI is optional but good practice.

Correct citations of RFCs can be found at: http://www.rfc-editor.org/in-notes/rfc-ref.txt (canonical) or at: http://www.durusau.net/standards/rfc/current/, where I maintain a list of current RFCs formatted for copying.