We suggest to read the following:

  1. Microformats site for calendar
    http://microformats.org/wiki/hcalendar
  2. HTML5 microformat for calendar
    http://microformats.org/wiki/HTML5
  3. Schema format
    http://schema.org/Event
  4. iCalendar format
    http://tools.ietf.org/html/rfc2445#page-136