Não informado. (1969). Eric news. Eric Clearinghouse on Teacher Education.
Chicago-referens (17:e uppl.)Não informado. Eric News. Washington: Eric Clearinghouse on Teacher Education, 1969.
MLA-referens (8:e uppl.)Não informado. Eric News. Eric Clearinghouse on Teacher Education, 1969.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.