http://www.rfc-editor.org/rfc/rfc4356.txt
RFC 4356: Mapping Between the Multimedia Messaging Service (MMS) and Internet Mail, R. Gellens2006-01-01T23:00:00-00:00This document specifies how to exchange messages between these two services, including mapping information elements as used in MMS X-Mms-* headers as well as delivery and disposition reports, to and from that used in SMTP and Internet message headers. [STANDARDS-TRACK]