Lithner, Stefan, and K Ingemar Jönsson. 2002. “Abundance of Owls and Bramblings Fringilla Montifringilla in Relation to Mast Seeding in South-Eastern Sweden”. Ornis Svecica 12 (1–2). Lund, Sweden:35-45. https://doi.org/10.34080/os.v12.22834.