Ottvall, R., Edenius, L., Elmberg, J., Engström, H., Green, M., Holmqvist, N., Lindström, Åke, Pärt, T., & Tjernberg, M. (2009). Population trends for Swedish breeding birds. Ornis Svecica, 19(3), 117–192. https://doi.org/10.34080/os.v19.22652