Middleton, B. A. and van der Valk, A. G. (1987) “The food habits of Greylag and Barheaded Geese in the Keoladeo National Park, India”, Wildfowl, pp. 94–102. Available at: https://tidsskrift.dk/Wildfowl/article/view/154807 (Accessed: 17 December 2025).