Chapman, F. M. (1896). Feeding-Habits of Purple Finches. Zenodo.
Lua i Stíl Chicago (17ú heag.)Chapman, Frank M. Feeding-Habits of Purple Finches. Zenodo, 1896.
Lua MLA (9ú heag.)Chapman, Frank M. Feeding-Habits of Purple Finches. Zenodo, 1896.
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