Hans-Dieter Burkhard Extending some Concepts of CBR - Foundations of Case Retrieval Nets. 17-50 1998 conf/iccbr/1998 Case-Based Reasoning Technology http://link.springer.de/link/service/series/0558/bibs/1400/14000017.htm db/conf/iccbr/cbr1998.html#Burkhard98