Förschler, M. I., L. Förschler, and U. Dorka. “Population Fluctuations of Siskins Carduelis Spinus, Common Crossbills Loxia Curvirostra, and Citril Finches Carduelis Citrinella in Relationship to Flowering Intensity of Spruce Picea Abies”. Ornis Fennica 83, no. 2 (July 1, 2006): 91–96. Accessed November 24, 2024. https://ornisfennica.journal.fi/article/view/133659.