References for encyclopedias should include the following elements:

For sources accessed online, include the retrieval date as the entry may change over time. In case the author is not available, the entry of the title will take the place of the author
Author Last Name, First Name. “Title of Entry.” Title of Reference Work, edition (if applicable), edited by Editor Name(s) (if applicable), vol. #, Publisher, Year, pp. ###–###.
American Medical Association. “Cardiovascular.” CPT 2021 Professional Edition, 2021, pp. 233–330.
Jamieson, Neil L. “Vietnamese.” Encyclopedia of Modern Asia, edited by David Levinson and Karen Christenson, vol. 6, Scribner’s, 2002.
“Ideology.” The American Heritage Dictionary, 3rd ed., 1997.
“Relativity.” Psychological Terms and Meanings, edited by Bruce Schulyer, 2nd ed., vol. 35, Bookies, 2005, pp. 235–238.
“Pollution.” A Dictionary of Environment and Conservation, 3rd ed., edited by Chris Park and Michael Allaby, Oxford University Press, 2017. Oxford Reference Online, https://www.oxfordreference.com/view/10.1093/acref/9780191826320.001.0001/acref-9780191826320. Accessed 18 Sept. 2025.
“Cryptocurrency.” Encyclopædia Britannica, 2024, https://www.britannica.com/topic/cryptocurrency. Accessed 12 Aug. 2025.