Benjamin Braatz Markus Klein Gunnar Schröter Matthias Bengel A Formal Component Concept for the Specification of Industrial Control Systems. 69-88 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3147&spage=69 2004 conf/dfg/2004 SoftSpez Final Report db/conf/dfg/softspez2004.html#BraatzKSB04