Clark, R G, S W Leach, K W Dufour, and M Gendron. 2013. “Wetland Fidelity of Female Mallard Anas Platyrhynchos and Gadwall Anas Strepera During Brood Rearing”. Wildfowl, April, 17-28. https://tidsskrift.dk/Wildfowl/article/view/153953.