Ulfvens, J. “Clutch Size, Productivity and Population Changes in a Population of the Horned Grebe Podiceps Auritus in an Exposed Habitat”. Ornis Fennica 66, no. 2 (July 1, 1989): 75–77. Accessed November 26, 2024. https://ornisfennica.journal.fi/article/view/133279.