Salim Ali & Dhillon, S. (2001). Handbook of the birds of India and Pakistan together with those of Bengladesh, Nepal, Bhutan and Srilanka: Vol-1: divers to hawks (2nd ed.). Oxford University Press.

Salim Ali and S. Dhillon. Handbook of the Birds of India and Pakistan Together with Those of Bengladesh, Nepal, Bhutan and Srilanka: Vol-1: Divers to Hawks. 2nd ed. New Delhi: Oxford University Press, 2001.

Salim Ali and S. Dhillon. Handbook of the Birds of India and Pakistan Together with Those of Bengladesh, Nepal, Bhutan and Srilanka: Vol-1: Divers to Hawks. 2nd ed. Oxford University Press, 2001.