Schünemann, Olivia, Alessa Jansen, Ulrike Willutzki, and Nina Heinrichs. “Allegiance and Treatment Quality As Moderators of the Comparative Effectiveness of Psychotherapy? A Systematic Review and Meta-Analysis of Studies Comparing Humanistic Psychotherapy to Other Psychotherapy Approaches”. Clinical Psychology in Europe 7, no. 1 (February 28, 2025): Article e9709. Accessed May 4, 2026. https://cpe.psychopen.eu/index.php/cpe/article/view/9709.