INTERNET-DRAFT Charles H. Lindsey Usenet Format Working Group University of Manchester April 2001
6.10. References The References header lists optionally CFWS-separated message identifiers of precursors. The content syntax makes use of syntax defined in [MESSFOR]. References-content = msg-id *( CFWS msg-id ) NOTE: This differs from the syntax of [MESSFOR] by requiring at least one CFWS between the msg-ids (this was an [RFC 1036] requirement). A followup MUST have a References header, and an article that is not a followup MUST NOT have a References header. In a followup, if the precursor did not have a References header, the followup's References-content MUST be formed by the message identifier of the precursor. A followup to an article which had a References header MUST have a References header containing the precursor's References- content (subject to trimming as described below) plus the precursor's message identifier appended to the end of the list (separated from it by CFWS). Followup agents SHOULD NOT trim message identifiers out of a References header unless the number of message identifiers exceeds 21, at which time trimming SHOULD be done by removing sufficient identifiers starting with the second so as to bring the total down to 21. However, it would be wrong to assume that References headers containing more than 21 message identifiers will not occur.[Previous Up Next]
See also previous draft (03): 6.8. References
See also previous draft (02): 6.4. References
See also previous draft (son-of-1036): 6_5__References
See also previous draft (rfc-1036): RFC1036_2_2_5__References