KNOWN ISSUES
       Some  sites  have  leading 0's on RFCs < 1000, ie, RFC0822
       may be rfc822.txt or rfc0822.txt.  I have yet to implement
       a  feature  to  work around this.  Most of the sub 1k RFCs
       have newer counter parts.  Look for "obsoleted by" in  the
       output from -k -s or -r to find the more up to date RFC.
       The real bug is the non-standardized rfc distibution.
       IETF.org has them with leading zeros, so I'm sticking with
       that.