[1] RFC 5965 - An Extensible Format for Email Feedback Reports ( 版) <http://tools.ietf.org/html/rfc5965>
[2] RFC Errata Report ( 版) <http://www.rfc-editor.org/errata_search.php?rfc=5965>
[3] RFC 6650 - Creation and Use of Email Feedback Reports: An Applicability Statement for the Abuse Reporting Format (ARF) ( 版) <http://tools.ietf.org/html/rfc6650>