subjectTerm: I. MATHEMATICS AND COMPUTER SCIENCE_or_II. NATURAL SCIENCES AND AGRICULTURAL SCIENCES__enauthor: Beligiannis, Apostolos_or_Gounaris, Anastasios_or_Bratsos, Athanasios_or_Vasileiadis, Nikolaos_or_Toumpis, Stavros_or_Kefalas, Petroslang: el