Não informado. (1958). Lead Abstracts. Lead Development Association.
Chicago-referens (17:e uppl.)Não informado. Lead Abstracts. London: Lead Development Association, 1958.
MLA-referens (8:e uppl.)Não informado. Lead Abstracts. Lead Development Association, 1958.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.