looking for xquery-related tutorial or book

hello, I am a newbie to XQuery,Could anybody introduce me some rudimental books or tutorials which can be freely downloaded from network.I only have a "XQuery:A Guided Tour" by Jonathan Robie and the W3C specification at hand.
	
thanks a lot



 Best regards
 Qiang Song
 Dept. of Computer Science, Tsinghua University
 
 
 2003-12-12