HÄRKÖNEN, Tero; ISAKSON, Erik. Status of harbour seals (Phoca vitulina) in the Baltic proper. NAMMCO Scientific Publications, Tromsø, Norway, v. 8, p. 71–76, 2010. DOI: 10.7557/3.2673. Disponível em: https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2673. Acesso em: 23 apr. 2026.