Andersson, Åke, Arne Follestad, Leif Nilsson, and Hakon Persson. 2001. “Migration Patterns of Nordic Greylag Geese Anser Anser”. Ornis Svecica 11 (1–2). Lund, Sweden:19-58. https://doi.org/10.34080/os.v11.22859.