Não informado. (2018). Report of the Secretary of the Smithsonian Institution. Smithsonian Institution.
Chicago-referens (17:e uppl.)Não informado. Report of the Secretary of the Smithsonian Institution. Washington: Smithsonian Institution, 2018.
MLA-referens (8:e uppl.)Não informado. Report of the Secretary of the Smithsonian Institution. Smithsonian Institution, 2018.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.