1. History of North American pinnipeds, a monograph of the walruses, sea-lions, sea-bears, and seals of North America;Allen;U.S. Geological and Geographical Survey of the Territories, Miscellaneous Publications,1880
2. Age determination and the growth and age distribution from cementum growth layers of bearded seals at Svalbard;Benjaminsen;Fiskeridirektoratets Skrifter Ser. Havundersokelser,1973
3. Contribution to the problem of the history of development of Caspian and Baikal seals;Chapskii;Trudy Zool. Inst. Akad. Nauk SSSR,1955
4. Macroscopic observations of the facial muscles in the Baikal seal (Phoca sibirica);Endo;Mar. Mamm. Sci.,1998
5. CT examination of the head of the Baikal seal (Phoca sibirica);Endo;J. Anat.,1999