M. Sivaram, P. S. Easa, and S. K. Abraham, “A Habitat Suitability Index Model for Nilgiri Tahr (<I>Hemitragus hylocrius</I> Ogilby) in Eravikulam National Park, Kerala”, Indian Forester, vol. 133, no. 10, pp. 1289–1304, Oct. 2007.