Didier Galmiche J.-M. Notin Connection-Based Proof Construction in Non-commutative Logic. 422-436 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2850&spage=422 2003 conf/lpar/2003 LPAR db/conf/lpar/lpar2003.html#GalmicheN03