http://www.rfc-editor.org/rfc/rfc2447.txt
RFC 2447: iCalendar Message-Based Interoperability Protocol (iMIP), F. Dawson, S. Mansour, S. Silverberg1998-11-01T23:00:00-00:00This document specifies a binding from the iCalendar Transport- independent Interoperability Protocol (iTIP) to Internet email-based transports. [STANDARDS-TRACK]