"Practical suggestions — Calculating numbers of pupils — Qualifications of teachers — Training of qualified inspectors in order to ensure that the audio-visual media are used to best effect in education." (Jean-Marie Van Bol, Abdelfattah Fakhfakh: The use of mass media in the developing countries. Brussels: CIDESA, 1971 Nr. 772, topic code 210.320, 410.320, 510)