- document
- TRAIL Onderzoeksschool (author) report 1995
- document
- TRAIL Onderzoeksschool (author) report 1994
- document
- Internationale vereniging Rijnschepen register (IVR) (author) report 1992
- document
- Kamer van Koophandel (author) report 1992
- document
- Permanent international association of navigation (author) report 1988