Härkönen, T., Stenman, O., Jüssi, M., Jüssi, I., Sagitov, R., & Verevkin, M. (1998). Population size and distribution of the Baltic ringed seal (<i>Phoca hispida botnica</i>). NAMMCO Scientific Publications, 1, 167–180. https://doi.org/10.7557/3.2986