American Sociological Association Style Guide, 7th edition by 
Cryptids are animals whose existence is disputed.(Hurn. 2016:1) Nessie is one example.(Cray 1959:258) Bigfoot is another cryptid.(Westrum 1980:27)
References
Cray, Ed. 1959. “Loch Ness Monster.” Western Folklore 18(3):258–59. doi: 10.2307/1497725.
Hurn, Samantha, ed. 2016. Anthropology and Cryptozoology: Exploring Encounters with Mysterious Creatures. New York: Routledge.
Westrum, Ron. 1980. “Sasquatch and Scientists: Reporting Scientific Anomalies.” Pp. 27–36 in Manlike Monsters on Trial: Early Records and Modern Evidence, edited by M. M. Halpin and M. M. Ames. Vancouver, BC: University of British Columbia Press.
Title: Anthropology and Cryptozoology: Exploring Encounters with Mysterious Creatures
Editor: Samantha Hurn
Publisher: Routledge
Place of Publication: New York
Date of Publication: 2016
Chapter Title: Sasquatch and Scientists: Reporting Scientific Anomalies
Chapter Author: Ron Westrum
Book Title: Manlike Monsters on Trial: Early Records and Modern Evidence
Book Editors: Marjorie M. Halpin and Michael M. Ames
Publisher: University of British Columbia Press
Place of Publication: Vancouver, BC
Date of Publication: 1980
Pages: 27-36
Article Title: Loch Ness Monster
Author: Ed Cray
Journal Title: Western Folklore
Volume: 18
Issue: 3
Date: 1959
Pages: 258-259