Kathleen Hornsby Max J. Egenhofer Identity-based change: a foundation for spatio-temporal knowledge representation. 207-224 2000 14 International Journal of Geographical Information Science 3 http://taylorandfrancis.metapress.com/openurl.asp?genre=article&issn=1365-8816&volume=14&issue=3&spage=207 db/journals/gis/gis14.html#HornsbyE00