RFC 1766 | Tags for the Identification of Languages. |
RFC 2045-2049 | MIME (Multipurpose Internet Mail Extensions) |
RFC 2047 | Part Three: Message Header Extensions for Non-ASCII Text. |
RFC 2183 | Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field. |
RFC 2231 | MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations. |