Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted. J. Galvin, S. Murphy, S. Crocker, et al. October 1995. http://www.faqs.org/rfcs/rfc1847.html
Communicating Presentation Information in Internet Messages: The Content-Disposition Header, R. Troost, S. Dorner. June 1995. http://www.faqs.org/rfcs/rfc1806.html
The Multipart/Report Content Type for the Reporting of Mail System Administrative Messages. G. Vaudreuil. January 1996. http://www.faqs.org/rfcs/rfc1892.html