- document
- Meijer, D.G. (author), Verheij, H.J. (author) report 1998
- document
- Verheij, H.J. (author), Kruse, G.A. (author), Niemeyer, J.H. (author), Sprangers, J.T.C.M. (author) report 1997
- document
- Meerendonk, E. van (author), Dekker, J. (author) report 1984
- document
- Jong, R.J. de (author) report 1970