Smithsonian Institution. (1926). Observations on birds of Argentina, Paraguay, Uruguay, and Chile. GPO.
Chicago Style (17th ed.) CitationSmithsonian Institution. Observations on Birds of Argentina, Paraguay, Uruguay, and Chile. [Washington]: GPO, 1926.
MLA (9th ed.) CitationSmithsonian Institution. Observations on Birds of Argentina, Paraguay, Uruguay, and Chile. GPO, 1926.
Warning: These citations may not always be 100% accurate.