Journal article (2007) - DE Kreft (author), C Berstone (author), B van der Meer (author), CR Geel (author), R Meyer (author), F May (author), R.J. Arts (author), A Obdam (author), R Svensson (author), S Eriksson (author), P Durst (author), I Gaus (author)

Journal article (1997) - C. Dekker (author), SJ Tans (author), B Oberndorff (author), R Meyer (author), LC Venema (author)