Διακήρυξη Declaration by the Association of Working Secondary Education Students (SEMME) concerning the assassination of Sotiris Petroulas - Σ.Ε.Μ.Μ.Ε. (Σύλλογος Εργαζομένων Μαθητών Μέσης Εκπαιδεύσεως); Association of Working Secondary School Pupils (SEMME)