[1] U.S. Fish and Wildlife Service. 2003. Final Revised Recovery Plan for the Southern Sea Otter (Enhydra lutris nereis). Portland, Oregon. Xi+pp.
[2] U.S. Geological Survey. 2005. Spring counts of southern sea otters, 1983-2005. USGS Western Ecological Research Center. Available at <www.werc.usgs.gov/otters/ca-surveydata.html>