9Andreas Voigtmann,Ludger Becker,Klaus H.Hinrichs Physical Design Aspects of anObject-Oriented Geo-Database Kernel Eighth International Workshop on Database and ExpertSystems Applications,1997.Proceedings,p529-534
10Thomas Devogele,Christine Parent,Stefano Spaccapietra On spatial databaseintegration International Journal of Geographical InformationScience,1998.VOL.12,NO.4,p335-352