[1] XBL 2.0 ( ( 版)) <http://dev.w3.org/2006/xbl2/Overview.html#extends>
[2] XBL 2.0 ( ( 版)) <http://dev.w3.org/2006/xbl2/Overview.html#binding-inheritance>
[3] XML Binding Language (XBL) 2.0 ( ( 版)) <http://www.w3.org/TR/2007/CR-xbl-20070316/#extends>