Mikhail Sheremet Dmitry Tishkovsky Frank Wolter Michael Zakharyaschev 'Closer' representation and reasoning. 2005 conf/dlog/2005 Description Logics http://www.ceur-ws.org/Vol-147/05-SherTishWolZak.pdf db/conf/dlog/dlog2005.html#SheremetTWZ05