Olofsson, E. “Winter Feeding by the Great Tit, Parus Major, on Eggs of the European Pine Sawfly, Neodiprion Sertifer”. Ornis Fennica 63, no. 3 (September 30, 1986): 91–92. Accessed May 16, 2024. https://ornisfennica.journal.fi/article/view/133213.