Jan Smid Marek Obitko David Fisher Walt Truszkowski Interaction and Communication of Agents in Networks and Language Complexity Estimates. 287-289 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3228&spage=287 2004 conf/faabs/2004 FAABS db/conf/faabs/faabs2004.html#SmidOFT04