Não informado. (1919). Scientific Survey of Porto Rico and the Virgin Islands. New York Academy of Sciences.
Chicago-referens (17:e uppl.)Não informado. Scientific Survey of Porto Rico and the Virgin Islands. New York: New York Academy of Sciences, 1919.
MLA-referens (8:e uppl.)Não informado. Scientific Survey of Porto Rico and the Virgin Islands. New York Academy of Sciences, 1919.
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