Bernard Lang Jean-François Abramatic Jesús M. González-Barahona Piera Gómez Mogens Kühn Pedersen Free and Proprietary Software in COTS-Based Software Development. 2 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3412&spage=2 2005 conf/iccbss/2005 ICCBSS db/conf/iccbss/iccbss2005.html#LangAGGP05