author: Bertachas, Ioannis_or_Gitzenis, Savvas_or_Giannakouris, Nikolaos_or_Fylaktakidou, Konstantina_or_Toumpis, Stavros__encollection: 3subjectTerm: I. MATHEMATICS AND COMPUTER SCIENCE_or_II. NATURAL SCIENCES AND AGRICULTURAL SCIENCEStype: 109lang: el