Clark, William S: The eagle genus Hieraaetus is distinct from Aquila, with comments on the name Ayres’ Eagle. Bulletin of the British Ornithologists' Club, 2012, 132. vsk, nro 4, s. 295–298. London: British Ornithologists' Club. Artikkelin verkkoversio (PDF). Viitattu 29.6.2021. (englanniksi) (Arkistoitu – Internet Archive)
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Clark, William S: The eagle genus Hieraaetus is distinct from Aquila, with comments on the name Ayres’ Eagle. Bulletin of the British Ornithologists' Club, 2012, 132. vsk, nro 4, s. 295–298. London: British Ornithologists' Club. Artikkelin verkkoversio (PDF). Viitattu 29.6.2021. (englanniksi) (Arkistoitu – Internet Archive)