collection: 3author: Toumpis, Stavros_or_Bertachas, Ioannis_or_Pavlakis, Konstantinos_or_Koumpis, Alexandros_or_Fylaktakidou, Konstantina_or_Toumpis, Stavros__ensubjectTerm: I. MATHEMATICS AND COMPUTER SCIENCE_or_II. NATURAL SCIENCES AND AGRICULTURAL SCIENCESlang: el