"The audio-visual media used in Nigeria include radio, television, the tape recorder, film transparencies, films, maps, teaching machines, etc. — About 700 schools northern Nigeria have radio and 50 have television sets." (Jean-Marie Van Bol, Abdelfattah Fakhfakh: The use of mass media in the developing countries. Brussels: CIDESA, 1971 Nr. 1663, topic code 54)