The sources you find at the library will contain citations to other sources. Don't ignore these citations; following citations is an important component of library research.
There are many different citation styles. Some sources may use in-text citations in parentheses, some will use footnotes or endnotes. When you encounter a citation that would be useful for your research, try to identify the title and author of the source. If it is a book, it will have a single title, but a journal article will include an article title and a journal title.
See the examples in the screenshots below. In some cases, you will have to turn to the references section (a.k.a. "works cited", "bibliography", etc.) for the complete information on a source.
In this example, following footnote 3 about the Istanbul Fire of 1660 leads to several sources, including the article "The Great Fire of 1660 and the Islamization of Christian and Jewish Space in Istanbul" by M.D. Baer.
This sentence about ecological agriculture practices cites Bommarco et al. We need to look up Bommarco et al in the references section to find the full citation.
The references section includes the article "Ecological Intensification: Harnessing Ecosystem Services for Food Security" by Bommarco, Kleijn, and Potts.
When you find a promising citation, look up the source. You can look up the title of the source (book title or article title) in LibrarySearch. Sometimes a citation will include a URL or DOI (digital object identifier). You can try using this link to access the source, but note that you may hit a paywall. If so, try looking up the source on a library computer.
Sometimes citations are hard to read and sources are hard to find. Contact a librarian for help.
You should always check with your instructor about what citation style is required for your assignment.
The Excelsior Online Writing Lab (OWL) has guides on APA, MLA, and Chicago Style documentation.