You can refer to the following links to understand more about the eXo Collaboration Reference Guide:

- GateIn:
   http://docs.jboss.com/gatein/portal/3.1.0-FINAL/reference-guide/en-US/html/index.html

- OpenSocial gadget:
  http://wiki.opensocial.org/index.php?title=Main_Page

- WebService:
  http://docs.jboss.org/exojcr/1.12.4-GA/developer/en-US/html/part-ws.html

- Chatserver:
	http://www.igniterealtime.org/builds/openfire/docs/latest/documentation/javadoc/index.html

- Vcard:
	http://en.wikipedia.org/wiki/VCard

- ICalendar standard:
	http://en.wikipedia.org/wiki/ICalendar
	http://www.ietf.org/rfc/rfc2445.txt
