Interesting links
- IOPS: Interuniversity Graduate School for Psychometrics and Sociometrics.
- VOC: The Dutch/Flemish Classification Society (in Dutch: Vereniging voor Ordinatie en Classificatie).
- IFCS: The International Federation of Classification Societies.
- Psychometrika: Journal for psychometrics.
- Journal of Classification: Journal for statistics.
- SPSS: Statistical software.
- Centre for Child and Family Studies, Leiden University (in Dutch: Algemene- en Gezinspedagogiek)
- Department of Education, Leiden University (in Dutch: Departement der Pedagogische Wetenschappen).
- Faculty of Social and Behavioral Sciences, Leiden University.