HARDING, Karin C; HÄRKÖNEN, Tero; HELANDER, Björn; KARLSSON, Olle. Status of Baltic grey seals: Population assessment and extinction risk. NAMMCO Scientific Publications, Tromsø, Norway, v. 6, p. 33–56, 2007. DOI: 10.7557/3.2720. Disponível em: https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2720. Acesso em: 11 may. 2026.