• Livro: Running Qmail - Autor: Richard Blum - Editora: Sams
• Livro: The Qmail Handbook - Autor: Dave Sill - Editora: Apress
• Site: www.lifewithqmail.org
• Site: www.qmail.org
• Site: http://www.nrg4u.com/
• Site: History of Email
• Site: http://www.livinginternet.com/
• Site: http://www.palomine.net/qmail/relaying.html
  
  Referências de RFCs

• RFC 821, Simple Mail Transfer Protocol (obsoleted by RFC 2821) http://www.ietf.org/rfc/rfc0821.txt
• RFC 822, Standard for the Format of ARPA Internet Text Messages (obsoleted by RFC 2822) http://www.ietf.org/rfc/rfc0822.txt
• RFC 931, Authentication Server. http://www.ietf.org/rfc/rfc0931.txt
• RFC 974, Mail Routing and the Domain System. http://www.ietf.org/rfc/rfc0974.txt
• RFC 1123, Requirements for Internet Hosts -- Application and Support. http://www.ietf.org/rfc/rfc1123.txt
• RFC 1413, Identification Protocol. http://www.ietf.org/rfc/rfc1413.txt
• RFC 1423, Privacy Enhancement for Internet Electronic Mail: Part III: Algorithms, Modes, and Identifiers. http://www.ietf.org/rfc/rfc1423.txt
• RFC 1651, SMTP Service Extensions. http://www.ietf.org/rfc/rfc1651.txt
• RFC 1652, SMTP Service Extension for 8bit-MIMEtransport. http://www.ietf.org/rfc/rfc1652.txt
• RFC 1806, Content disposition. header. http://www.ietf.org/rfc/rfc1806.txt
• RFC 1854, SMTP Service Extension for Command Pipelining. http://www.ietf.org/rfc/rfc1854.txt
• RFC 1891, SMTP Service Extension for Delivery Status Notifications. http://www.ietf.org/rfc/rfc1891.txt
• RFC 1892, The Multipart/Report Content Type for the Reporting of Mail System Administrative Messages. http://www.ietf.org/rfc/rfc1892.txt
• RFC 1893, Enhanced mail system status codes. http://www.ietf.org/rfc/rfc1893.txt
• RFC 1894, An Extensible Message Format for Delivery Status Notifications. http://www.ietf.org/rfc/rfc1894.txt
• RFC 1939, Post Office Protocol - Version 3. http://www.ietf.org/rfc/rfc1939.txt
• RFC 1985, SMTP Service Extension for Remote Message Queue Starting (ETRN). http://www.ietf.org/rfc/rfc1985.txt
• RFC 1991, PGP Message Exchange Formats. http://www.ietf.org/rfc/rfc1991.txt
• RFC 2015, MIME Security with Pretty Good Privacy. (PGP). http://www.ietf.org/rfc/rfc2015.txt
• RFC 2045, MIME Internet message bodies. http://www.ietf.org/rfc/rfc2045.txt
• RFC 2046, MIME Media Types. http://www.ietf.org/rfc/rfc2046.txt
• RFC 2047, MIME Headers. http://www.ietf.org/rfc/rfc2047.txt
• RFC 2048, MIME Registration Procedures. http://www.ietf.org/rfc/rfc2048.txt
• RFC 2049, MIME Conformance Criteria. http://www.ietf.org/rfc/rfc2049.txt
• RFC 2142, Mailbox names for common services. http://www.ietf.org/rfc/rfc2142.txt
• RFC 2183, Content Disposition header. http://www.ietf.org/rfc/rfc2183.txt
• RFC 2821, Simple Mail Transfer Protocol. http://www.ietf.org/rfc/rfc2821.txt
• RFC 2822, Internet Message Format http://www.ietf.org/rfc/rfc2822.txt