Ryttman, Hans. 1994. “Estimates of Survival and Population Development of the Osprey Pandion Haliaetus, Common Buzzard Buteo Buteo, and Sparrowhawk Accipiter Nisus in Sweden”. Ornis Svecica 4 (4). Lund, Sweden:159-72. https://doi.org/10.34080/os.v4.23018.