KNORTH, Erik J. In Memoriam: Joop Hellendoorn (1939-2025). Jeugd in Ontwikkeling , [S. l.], 2025. DOI: 10.54447/JiO.21875. Disponível em: https://jeugdinontwikkeling.nl/article/view/21875.. Acesso em: 25 nov. 2025.