Mikyeong Moon Keunhyuk Yeom An Approach to Develop Requirement as a Core Asset in Product Line. 23-34 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3107&spage=23 2004 conf/icsr/2004 ICSR db/conf/icsr/icsr2004.html#MoonY04