1. An overview of sea otter studies;Ballachey,1994
2. Barabash-Nikiforov, I.I., 1947. The sea otter. Translated from Russian by A. Birron and Z.S. Cole for the National Science Foundation by the Israel program for scientific translations, Jeruselam, 1962, 227 pp.
3. Sea otter;Bodkin,2003
4. Bodkin, J.L., Ballachey, B.E., 2010. Modeling the effects of mortality on sea otter populations. US Geological Survey Scientific Investigations Report, 2010–5096, pp. 12.
5. An aerial survey method to estimate sea otter abundance;Bodkin,1999