Herceg Mandić, Vera, Anđelija Ivkov Džigurski, Ljubica Ivanović Bibić, and Smiljana Đukičin. 2016. “Modeling the Geography Class through Problem-Based Teaching: A Case Study from Novi Sad, Serbia”. Journal of Subject Didactics 1 (1), 13-23. https://doi.org/10.5281/zenodo.55471.