Wittlich C, Brühne T. Operationalisation of ESD Criteria for the Inventory of Out-of-School ESD Learning Places in Rhineland-Palatinate. ZGD [Internet]. 2022 Nov. 22 [cited 2026 Apr. 3];50(1):1-19. Available from: https://www.zgd-journal.de/index.php/zgd/article/view/47