An RFC from the IETF, this is part 5 in the MIME standard,
- Full text of RFC 2049 Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples. N. Freed, N. Borenstein. November 1996. (Format: TXT=51207 bytes) (Obsoletes RFC 1521, RFC 1522, RFC 1590) (Status: DRAFT STANDARD)