@misc{ enwiki:1231087155, author = "{Wikipedia contributors}", title = "S51 and S81 buses --- {Wikipedia}{,} The Free Encyclopedia", year = "2024", url = "https://en.wikipedia.org/w/index.php?title=S51_and_S81_buses&oldid=1231087155", note = "[Online; accessed 12-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:1231087155, author = "{Wikipedia contributors}", title = "S51 and S81 buses --- {Wikipedia}{,} The Free Encyclopedia", year = "2024", howpublished = "\url{https://en.wikipedia.org/w/index.php?title=S51_and_S81_buses&oldid=1231087155}", note = "[Online; accessed 12-July-2024]" }