Charles W. Krueger Birgit Geppert How Can Testing Keep Pace with Accelerated Development in Software Product Line Engineering? 308-309 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3154&spage=308 2004 conf/splc/2004 SPLC db/conf/splc/splc2004.html#Geppert04