The original documentation from where this document has been obtained can be found in the man pages from "mutt", "pgp", "pgp5", "gnupg", "procmail", in the respectives directories in /usr/doc and in the world wide web sites: .:: speakerdeck.com ::. .:: nl.pinterest.com ::. .:: mpc.imu.edu.kg ::.
The recommendations (request for comments, RFC) that are referenced in this document are: [Web Specs: Pandas] .:: fyers.in ::.
and can be found in /usr/doc/doc-rfc and in various sites in the world wide web, like .:: giphy.com ::. .:: 166bet-1.gitbook.io ::. http://metalab.unc.edu and http://nic.mil. You can get information from RFCs in RFC-INFO@ISI.EDU