Ken Schwaber Agile Implementations, Agile Impediments, and Agile Management. 227 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3134&spage=227 2004 conf/xpu/2004xpu XP/Agile Universe db/conf/xpu/xpu2004.html#Schwaber04