B. Desruisseaux. <a href="http://www.rfc-editor.org/rfc/rfc5545.txt"><cite>Internet Calendaring and Scheduling Core Object Specification (iCalendar).</cite></a> September 2009. Internet RFC 5545. URL: <a href="http://www.rfc-editor.org/rfc/rfc5545.txt">http://www.rfc-editor.org/rfc/rfc5545.txt</a>