Ikawa, Hiroshi, and Marie-Jo Ikawa. “Autumn and Spring Migration of the Taiga Bean Goose Anser Fabalis Middendorffii in Northern Japan from 2002 to 2012, With Implications for Site Conservation”. Wildfowl, Dec. 2013, pp. 40-55, https://tidsskrift.dk/Wildfowl/article/view/153600.