Não informado. (1932). National Elementary Principal. National Association of Elementary School Principals.
Chicago-referens (17:e uppl.)Não informado. National Elementary Principal. Arlington, Va: National Association of Elementary School Principals, 1932.
MLA-referens (8:e uppl.)Não informado. National Elementary Principal. National Association of Elementary School Principals, 1932.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.