Não informado. (1989). Educational Technology Research and Development. Association for Educational Communications and Technology.
Citação do estilo Chicago (17ª ed.)Não informado. Educational Technology Research and Development. Washington: Association for Educational Communications and Technology, 1989.
Citação MLA (8ª ed.)Não informado. Educational Technology Research and Development. Association for Educational Communications and Technology, 1989.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.