Não informado. Visual education. National Committee for Visual Aids in Education.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Visual Education. London: National Committee for Visual Aids in Education.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Visual Education. National Committee for Visual Aids in Education.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.