Avgeris, Antonios, Panagiota Sergaki, Achilleas Kontogeorgos, and Antonios Tiganis. “RECIPROCITY IN STUDENT GROUPS: EXPERIMENTAL EVIDENCE FROM GREECE”. International Journal of Economic Sciences 9, no. 1 (June 20, 2020): 44–67. Accessed April 30, 2025. https://www.ijes-journal.org/journal/article/view/74.