Não informado. (1941). Bell Telephone Magazine. American Telephone and Telegraph Company.
Chicago-referens (17:e uppl.)Não informado. Bell Telephone Magazine. New York: American Telephone and Telegraph Company, 1941.
MLA-referens (8:e uppl.)Não informado. Bell Telephone Magazine. American Telephone and Telegraph Company, 1941.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.