Sharpe, R. B., & Robert, P. (1889). Sharpe's Birds in Nature. Zenodo.
Cita Chicago (17th ed.)Sharpe, Richard Bowdler, i P. Robert. Sharpe's Birds in Nature. Zenodo, 1889.
Cita MLA (9th ed.)Sharpe, Richard Bowdler, i P. Robert. Sharpe's Birds in Nature. Zenodo, 1889.
Atenció: Aquestes cites poden no estar 100% correctes.