Não informado. (2018). Report of the Secretary of the Smithsonian Institution. Smithsonian Institution.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Report of the Secretary of the Smithsonian Institution. Washington: Smithsonian Institution, 2018.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Report of the Secretary of the Smithsonian Institution. Smithsonian Institution, 2018.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.