* Mutt on Zimbra
    * https://nixtricks.wordpress.com/2010/05/05/mutt-configure-mutt-to-receive-email-via-imap-and-send-via-smtp/
  * GG Contact on mutt
    * https://hynek.me/articles/my-mutt-gmail-setup/
    * https://medium.com/cheng-zhen/mutt-with-google-contact-ab67ac238a37
  * Mutt 4 Exchange
    * http://donnlee.com/2010/01/22/do-you-love-mutt-use-offlineimap-fdm-and-rejoice/