↑ "Otary, n., etymology of" The Oxford English Dictionary. 2nd ed. 1989. OED Online. Oxford University Press. http://dictionary.oed.com/ Accessed November 2007
↑ (tiếng Nhật) Zalophus californianus japonicus (CR), Red Data Book, Japan Integrated Biodiversity Information System, Ministry of the Environment (Japan). "The Japanese sea lion (Zalophus californianus japonicus) was common in the past around the coast of the Japanese Archipelago, but declined rapidly after the 1930s from overhunting and increased competition with commercial fisheries. The last record in Japan was a juvenile, captured in 1974 off the coast of Rebun Island, northern Hokkaido."
