Gérard D. Cohen Hans Georg Schaathun Separating Codes: Constructions and Bounds. 322-328 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2976&spage=322 2004 conf/latin/2004 LATIN db/conf/latin/latin2004.html#CohenS04