Journal article (1999) - MJG Jak (author), VWJ Verhoeven (author), I.M. de Schepper (author), F.M. Mulder (author), F. M. Mulder (author), FM Mulder (author), Fokko Mulder (author), Fokko M. Mulder (author), E.M. Kelder (author), E. M. Kelder (author), Erik Kelder (author), Erik M. Kelder (author), J. Schoonman (author)