Enea Zaffanella Patricia M. Hill Roberto Bagnara Decomposing Non-redundant Sharing by Complementation. 69-84 1999 conf/sas/1999 SAS http://link.springer.de/link/service/series/0558/bibs/1694/16940069.htm db/conf/sas/sas99.html#ZaffanellaHB99