Why Cite?
Citation is the practice of providing information about the sources you have used in your writing. This allows readers to trace ideas back to their original sources and gives credit to the original author.
Citation acknowledges any source that has directly influenced your language, ideas, or arguments. You should cite not only what you quote, but also what you paraphrase.
If you don't cite, you may be guilty of plagiarism.
Elements of a Citation
While the exact parts of a citation vary from one source type to the next, the most common elements address the questions who, what, when, and where.
Who
This is the name of the person (author, composer, artist) who is responsible for the work being cited. It may be an institution rather than an individual, as in many government documents.
What
The title of the work
When
The date of the item being cited. Usually, only the year is required, but if you have more specific information, you can include that as well.
Where
Where can someone who is interested in this source find it? This information may include one or more of the following:
- Publication title (with volume, number, and page numbers)
- URL - for example, http://www.cnn.com/2017/04/07/politics/xi-trump-summit-syria/
- DOI (digital object identifier) - for example, 10.1016/j.nut.2015.05.021
Reading a Citation
Sample Citation in APA Style
Reference Lists & In-Text Citations
Correctly citing a work is a two-part process.
The Reference List
This lists the complete details of every item you cite. It is located at the end of your paper.
A full APA-style citation for a scientific paper might look like this:
Pont, C., Wagner, S., Kremer, A., Orlando, L., Plomion, C., & Salse, J. (2019). Paleogenomics: reconstruction of plant evolutionary trajectories from modern and ancient DNA. Genome Biology, 20(1), 29–17. https://doi.org/10.1186/s13059-019-1627-1
In-Text Citations
These occur within the body of your paper, either as parenthetical notes or as footnotes. These give a shorter form of the citation. Interested readers can refer to your reference list for complete details.
The in-text citation for the paper listed above might look like this:
DNA sequences from subfossil remains can inform our understanding of modern plant genome organization (Pont et al., 2019).
Citation Styles
Many different organizations and publications have developed rules for how sources should be cited. For undergraduate work, APA, MLA, and Chicago are the most used. Make sure that you follow the rules of the style preferred by your instructor. If your instructor just says, "be consistent," pick one of the common styles to use. For information on specific styles, see our Citation Styles page.
Citation Managers
Writing bibliographies can be tedious and time-consuming. Luckily, there are free tools that will create them for you. Such tools will let you collect a set of sources and then drop them into your paper as you type. We recommend Zotero (our guide).