... and more MIME RFCs ...
1437 "The Extension of MIME Content-Types to a New Medium"
1652 "SMTP Service Extension for 8bit MIMEtransport"
1651 "SMTP Service Extensions"
1556 "Handling of Bi-directional Texts in MIME"
1740 "MIME Encapsulation of Macintosh files - MacMIME"
1741 "MIME Content Type for BinHex Encoded Files"