Reachability Problems in Entity-Relationship Schema Instances.

Sebastiano Vigna Reachability Problems in Entity-Relationship Schema Instances. 96-109 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3288&spage=96 2004 conf/er/2004 ER db/conf/er/er2004.html#Vigna04