- document
- Liu, D.K. (author), van leeuwen, J.L. (author), van Delft, D.R.V. (author) report 1993
- document
- Liu, D.K. (author), van Leeuwen, J.L. (author), van Delft, D.R.V. (author) report 1993
- document
- Liu, K. (author), Noordhoek, C. (author), van Delft, D.R.V. (author) report 1991
- document
- Liu, K. (author), Noordhoek, C. (author), van Delft, D.R.V. (author), van de Vegte, G.J. (author) report 1990