Não informado. (1936). Frontiers: A magazine of natural history. Academy of Natural Sciences of Philadelphia.
Chicago-referens (17:e uppl.)Não informado. Frontiers: A Magazine of Natural History. Philadelphia, Pa: Academy of Natural Sciences of Philadelphia, 1936.
MLA-referens (8:e uppl.)Não informado. Frontiers: A Magazine of Natural History. Academy of Natural Sciences of Philadelphia, 1936.
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