Olivier Hermant Semantic Cut Elimination in the Intuitionistic Sequent Calculus. 221-233 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3461&spage=221 2005 conf/tlca/2005 TLCA db/conf/tlca/tlca2005.html#Hermant05