Voslamber, Berend, Elise Knecht, and David Kleijn. “Dutch Greylag Geese Anser Anser: Migrants or Residents?”. Ornis Svecica 20, no. 3–4 (October 1, 2010): 207–214. Accessed May 6, 2024. https://journals.lub.lu.se/os/article/view/22626.