Hario, M., and J. Uuksulainen. “Mercury Load According to Moulting Area in Primaries of the Nominate Race of the Lesser Black-Backed Gull Larus F. Fuscus”. Ornis Fennica, vol. 70, no. 1, Mar. 1993, pp. 32–39, https://ornisfennica.journal.fi/article/view/133361.