Van de Vijver, E., H. Verkade, and P. F. van Rheenen. “Chronic Abdominal Pain, Fatigue and Inflammatory Bowel Disease in Children: PhD Thesis Presented on November 4th, 2020 at University of Groningen”. Belgian Journal of Paediatrics, vol. 23, no. 2, July 2021, https://www.belgjpaediatrics.com/index.php/bjp/article/view/158.