Felix Bachmann Michael Goedicke Julio Cesar Sampaio do Prado Leite Robert L. Nord Klaus Pohl Balasubramaniam Ramesh Alexander Vilbig A Meta-model for Representing Variability in Product Family Development. 66-80 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3014&spage=66 2003 conf/pfe/2003 PFE db/conf/pfe/pfe2003.html#BachmannGLNPRV03