Hakala, A. V. K., and E. S. Nyholm. “Two Nests of the Two- Barred Crossbill Loxia Leucoptera in Kuusamo in 1971”. Ornis Fennica 50, no. 1 (March 31, 1973): 46–47. Accessed April 20, 2025. https://ornisfennica.journal.fi/article/view/132848.