@misc{ enwiki:1228081917, author = "{Wikipedia contributors}", title = "Definite matrix --- {Wikipedia}{,} The Free Encyclopedia", year = "2024", url = "https://en.wikipedia.org/w/index.php?title=Definite_matrix&oldid=1228081917", note = "[Online; accessed 9-July-2024]" }
url
(\usepackage{url}
somewhere in the preamble), which tends to give much more nicely formatted web addresses, the following may be preferred:
@misc{ enwiki:1228081917, author = "{Wikipedia contributors}", title = "Definite matrix --- {Wikipedia}{,} The Free Encyclopedia", year = "2024", howpublished = "\url{https://en.wikipedia.org/w/index.php?title=Definite_matrix&oldid=1228081917}", note = "[Online; accessed 9-July-2024]" }