Παπάρας Δημήτριος, and Πούλος Ανδρέας. “Πτυσάγωνα”. Open Schools Journal for Open Science 3, no. 6 (July 21, 2020). Accessed April 2, 2025. https://ejournals.epublishing.ekt.gr/index.php/openschoolsjournal/article/view/24313.