Nilsson, Leif, Arne Follestad, Matthieu Guillemain, Vincent Schricke, and Berend Voslamber. 2013. “France As a Staging and Wintering Area for Greylag Geese Anser Anser”. Wildfowl, December, 24-39. https://tidsskrift.dk/Wildfowl/article/view/153599.