Alexandra Musto Klaus Stein Kerstin Schill Andreas Eisenkolb Wilfried Brauer Qualitative Motion Representation in Egocentric and Allocentric Frames of Reference. 461-476 http://link.springer.de/link/service/series/0558/bibs/1661/16610461.htm 1999 conf/cosit/1999 COSIT db/conf/cosit/cosit99.html#MustoSSEB99