United States. Census Office, Emmons, S. F., & Becker, G. F. (1885). Statistics and technology of the precious metals. GPO.
Chicago-referens (17:e uppl.)United States. Census Office, Samuel Franklin Emmons, och George F. Becker. Statistics and Technology of the Precious Metals. Washington: GPO, 1885.
MLA-referens (8:e uppl.)United States. Census Office, et al. Statistics and Technology of the Precious Metals. GPO, 1885.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.