[1] Foster, Michael Dylan. "The metamorphosis of the kappa: transformation of folklore to folklorism in Japan." Asian Folklore Studies, vol. 56, no. 1, 1998, p. 1+. Academic OneFile, http://link.galegroup.com.pitt.idm.oclc.org/apps/doc/A53857506/AONE?u=upitt_main&sid=AONE&xid=236d78ef. Accessed 10 Oct. 2018.
[2] Foster, Michael Dylan. The Book of Yokai : Mysterious Creatures of Japanese Folklore, University of California Press, 2015. ProQuest Ebook Central, https://ebookcentral.proquest.com/lib/pitt-ebooks/detail.action?docID=1710992.
[3] Ashkenazi, Michael. Handbook of Japanese Mythology. ABC-CLIO, 2003. EBSCOhost, search.ebscohost.com/login.aspx?direct=true&AuthType=ip,uid&db=nlebk&AN=100028&scope=site.
[4] Foster, Michael Dylan. Pandemonium and Parade: Japanese Monsters and the Culture of Yōkai. Berkeley: University of California Press, 2009.
[5] Yanagita, Kunio, et al. Folk Legends from Tono: Japan's Spirits, Deities, and Phantastic Creatures. Rowman & Littlefield Publishing Group, Inc., 2015.
[6] “Kappa.” Yokai Wiki, FANDOM, yokai.fandom.com/wiki/Kappa.