Gerard, J. (1889). Science and Scientists: Some Papers on Natural History: No. VI. Instinct and Its Lessons. London.
Lua i Stíl Chicago (17ú heag.)Gerard, John. Science and Scientists: Some Papers on Natural History: No. VI. Instinct and Its Lessons. London, 1889.
Lua MLA (8ú heag.)Gerard, John. Science and Scientists: Some Papers on Natural History: No. VI. Instinct and Its Lessons. London, 1889.
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