Não informado. (1974). Special Education. National Council for Special Education.
Chicago-referens (17:e uppl.)Não informado. Special Education. London: National Council for Special Education, 1974.
MLA-referens (8:e uppl.)Não informado. Special Education. National Council for Special Education, 1974.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.