Please use a single type of refernce style and be consistent. I encourage you to use an automated/online bibliography maker. My personal favourite is to use the one that comes equipped with LaTeX called bibtex. You can often get bibtex entries from sites such as https://mathscinet.ams.org/mathscinet for mathematical papers as an example. Failing this, try a site like https://www.easybib.com/ which also allows you to download bibtex entries to compile with you LaTeX source code. Any correct and consistent references list that follows a reasonable standard will be accepted (must be in alphabetical order, websites must have dates accessed and so on). Make sure content is cited inline (preferred) or footnotes to relevant entries are given. Note that mathematics does not have a set standard for citations.
It is important to cite your evidence where appropriate. While there is no formal requirement to have a reference in your paper, citing evidence will certainly make your paper much stronger than a paper without citations. Note however that citing too much evidence detracts from the paper having your voice in it. Striking a balance between these two extremes is difficult but is imperative to do to produce a high quality university level paper.
For those that want to learn a style from scratch, a useful style is the Modern Languages Association of America (MLA) at http://library.concordia.ca/help/citing/mla.php or more generally, visit https://lib.uwaterloo.ca/web/dictionaries-encyclopedia-and-more/citation-style-guides for a collection of curated style guides.
Last revised 7 November 2023.