There are thousands of citation styles in use. Your lecturer may tell you to use a particular one, or allow you to choose one on your own.
Guides for each style will tell you how to format the references:
- Details on which order to present the bibliographic information.
- Grammar instructions such as how to use punctuation and capitalisation - what is emboldened, underlined, italicised… where the full stops and commas go…
- Different rules will apply to different formats of sources (journal articles, book with one author, books with several authors, edited books, chapters in edited books, webpages, reports, films, etc. etc…)
Many different styles are in use in Trinity College Dublin - for definitive answers you should use the full style manual for each system.