usefor-usefor-03 April 2005

3.2.10  Xref

   The Xref header indicates where an article was filed by the last
   serving agent to process it.  The article locations are used to keep
   track of crossposted articles so that reading agents serviced by a
   particular serving agent can mark such articles as read.
   xref            =  "Xref:" SP [CFWS] server-name
            1*( CFWS location ) [CFWS] CRLF

   server-name     =  path-identity

   location        =  newsgroup-name ":" article-locator

   article-locator =  1*( %x21-27 / %x29-3A / %x3C-7E )
            ; US-ASCII printable characters
            ; except '(' and ';'

   The <server-name> is included so that software can determine which
   serving agent generated the header.  The locations specify what
   newsgroups the article was filed under (which may differ from those
   in the Newsgroups header) and where it was filed under them.  The
   exact form of an article-locator is implementation-specific.

      NOTE: The traditional form of an article-locator (as required by
      [NNTP]) is a decimal number, with articles in each newsgroup
      numbered consecutively starting from 1.

--- ../usefor-usefor-02/Xref.out          November 2004
+++ ../usefor-usefor-03/Xref.out          April 2005
@@ -21,7 +21,7 @@
    in the Newsgroups header) and where it was filed under them.  The
    exact form of an article-locator is implementation-specific.
 
-      NOTE: The traditional form of an article-locator (as used by
+      NOTE: The traditional form of an article-locator (as required by
       [NNTP]) is a decimal number, with articles in each newsgroup
       numbered consecutively starting from 1.