subjectTerm: I. MATHEMATICS AND COMPUTER SCIENCE_or_II. NATURAL SCIENCES AND AGRICULTURAL SCIENCES__enauthor: Kefalas, Petros_or_Pagourtzis, Aristeidis_or_Sakellariou, Ilias_or_Beligiannis, Apostolos_or_Toumpis, Stavros_or_Stamatis, Dimosthenis_or_Spyropoulos, Vasileioslang: el