Não informado. (1975). The Bell Journal of Economics. American Telephone and Telegraph Company.
Chicago-referens (17:e uppl.)Não informado. The Bell Journal of Economics. New York: American Telephone and Telegraph Company, 1975.
MLA-referens (8:e uppl.)Não informado. The Bell Journal of Economics. American Telephone and Telegraph Company, 1975.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.