F. Dawson, T. Howes. <a href="http://www.ietf.org/rfc/rfc2426.txt"><cite>vCard MIME Directory Profile.</cite></a> September 1998. URL: <a href="http://www.ietf.org/rfc/rfc2426.txt">http://www.ietf.org/rfc/rfc2426.txt</a>