Elisabeth Weissensteiner Stephan Winter Landmarks in the Communication of Route Directions. 313-326 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3234&spage=313 2004 conf/giscience/2004 GIScience db/conf/giscience/giscience2004.html#WeissensteinerW04