Audubon, J. J. (1840). Great Horned Owl, Buro virginianus, Gmel. [Pl. 39]. Zenodo.
Cita Chicago (17th ed.)Audubon, John James. Great Horned Owl, Buro Virginianus, Gmel. [Pl. 39]. Zenodo, 1840.
Cita MLA (9th ed.)Audubon, John James. Great Horned Owl, Buro Virginianus, Gmel. [Pl. 39]. Zenodo, 1840.
Atenció: Aquestes cites poden no estar 100% correctes.