Harding, Karin C, Tero Härkönen, Björn Helander, and Olle Karlsson. “Status of Baltic grey seals: Population assessment and extinction risk”. NAMMCO Scientific Publications 6 (January 1, 2007): 33–56. Accessed January 8, 2025. https://new.eludamos.org/index.php/NAMMCOSP/article/view/2720.