Korpimäki, Erkki, Heimo Mikkola, and Risto Tornberg. “Professor Emeritus Seppo Sulkava (1931–2019)”. Ornis Fennica 96, no. 2 (July 1, 2019): 100. Accessed May 10, 2024. https://ornisfennica.journal.fi/article/view/133951.