1. Geotechniek—Algemen gedeelte en belastingen;Anonymous,1991
2. GIS1 and BIS2 in local authorities: panel discussion;Newsletter of the Engineering Geology Circle,1990
3. Infrastructure for Princes' day [opening of Parliament: Queen's speech]: New metro for Amsterdam and Rotterdam;Dekker;Ingenieurskrant,1993
4. Ingeobase, Design and Implementation of an Engineering Geological Database;Herbschleb,1990
5. Politics of Underground Transport Systems in Utrecht (summary only);Kernkamp,1993