Fernando Orejas Elvira Pino On the Integration of Modular Heterogeneous Specifications. 582-601 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3147&spage=582 2004 conf/dfg/2004 SoftSpez Final Report db/conf/dfg/softspez2004.html#OrejasP04