When should you quote a source?

The number of sources you cite in your paper depends on the purpose of your work. For most papers, cite one or two of the most representative sources for each key point. Literature review papers, however, typically include a more exhaustive list of references.

Provide appropriate credit to the source (e.g., by using an in-text citation) whenever you do the following:

  • paraphrase (i.e., state in your own words) the ideas of others
  • directly quote the words of others
  • refer to data or data sets
  • reprint or adapt a table or figure, even images from the internet that are free or licensed in the Creative Commons
  • reprint a long text passage or commercially copyrighted test item

Avoid both undercitation and overcitation. Undercitation can lead to plagiarism and/or self-plagiarism. Overcitation can be distracting and is unnecessary.

For example, it is considered overcitation to repeat the same citation in every sentence when the source and topic have not changed. Instead, when paraphrasing a key point in more than one sentence within a paragraph, cite the source in the first sentence in which it is relevant and do not repeat the citation in subsequent sentences as long as the source remains clear and unchanged.

Figure 8.1 in Chapter 8 of the Publication Manual provides an example of an appropriate level of citation.

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Regardless if you paraphrase, summarize, or directly quote ideas from an outside source, in-text citations are necessary in order to give proper credit to the original authors of those ideas.

  • When you present ideas in a sentence that are un-cited, it is assumed those are your own original ideas.
  • Including just one citation at the end of a paragraph is not sufficient unless the last sentence is the only information in the paragraph that came from the cited source.
  • Cite sources often and correctly throughout a paragraph in order to avoid unintentional plagiarism.

Citing multiple sentences from the same source can feel repetitive and awkward. To avoid repetition and improve readability of a summarized or paraphrased paragraph, follow these suggestions.

  • Open with a signal phrase or narrative citation.
    • According to recent study by Smith (2017)…
  • Follow with clues that make it clear you are still referring to ideas by Smith.
  • Follow with a parenthetical citation.
    • [Written text]… (Smith, 2017).
  • Continue mixing these citation approaches throughout the paragraph.

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What is a source? 

If someone else created it, and you’re using it in your work, it’s a source. Lots of things can be sources, including books, articles, websites, manuscripts, photographs, films, speeches, music, interviews, emails, videos, phone calls, tweets, and many more.

What is common knowledge? 

Here is the definition of “common knowledge,” taken from the UMW Honor System Guidebook and Constitution:

Common knowledge -- information quickly accessible to the reader of a given document. The reader need not actually know the information, but must be able to check its accuracy quickly in any good library without citations from the author of the paper. Usually, the reader should also be able to check or pursue the information in a variety of published sources. Such common or readily available information does not require documentation. But if the reader does need to use a particular source to follow up or verify the information, a reference to that source is necessary.

It’s often difficult to determine whether something counts as common knowledge. If you’re unsure, play it safe -- cite it!

What if I reuse an idea or sentence from a paper that I wrote for a previous class? Do I need to cite my own paper? 

You may not reuse content from your previously submitted work unless you have your professor’s permission. If you do have your professor’s permission, then you may reuse your own content, but you should include a citation to your previously submitted work, so that your reader knows where the content originated.

If I didn’t use a particular source, do I still need to put that source in my bibliography? 

In most cases, no. Your bibliography should only include sources that you use. However, there are exceptions to this rule, especially for higher-level work such as senior theses. If you’re not sure, talk to your professor.


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When should you quote a source?
Zotero is free. It runs on Mac, Windows, and Linux. It's compatible with Firefox, Chrome, and Safari.

You'll need to do two things:

  1. Download the Zotero app
  2. Install the Zotero connector for your browser.

Both can be downloaded if you click the "Get Zotero" logo. 


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Zotero lets you save citation information from the UMW library catalog, from most of the library databases, and from some popular websites such as Amazon or the New York Times, with just one click. Whenever you view a webpage that contains information about a book or article, Zotero will display an icon at the top of your browser, near the address bar. Just click the icon and Zotero will automatically save the information.

When should you quote a source?

The icon will look different depending on what type of thing you're viewing. You might see  for a journal article, or  for a book, or  for a newspaper article, or any of a wide variety of other icons.

If you're viewing a page that has lots of different items on it, such as a list of search results, Zotero will display a folder icon. Click the folder icon to get a list of all the items on the page. Then, check off the ones you want to save.

When should you quote a source?


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Zotero lets you create "collections" to organize your items. Collections are like file folders on your computer, but an item can be in more than one collection at a time. For example, a book on the Civil War could be filed in your "Civil War" collection, your "Virginia History" collection and your "19th Century America" collection all at the same time, without having to make three copies of it.

To create a collection, click the button that looks like a folder with a green plus sign. You can find it at the top left of the Zotero window.

When should you quote a source?

In general, you must document sources when you provide information that you ordinarily would not have known before conducting your research, and when you provide information that it cannot be assumed the reader knows. You must cite a reference when you:

  • Discuss, summarize, or paraphrase the ideas of an author
  • Provide a direct quotation
  • Use statistical or other data
  • Use images, graphics, videos, and other media

While you are doing research and locating sources, be sure to document materials thoroughly, noting the author, title, publisher, place of publication, date, and page numbers of all sources used. For electronic materials, you should also note the DOI number (Digital Object Identifier) if available. Note the URL of any website you consult; depending on the source, you may need it for the reference.

APA style no longer requires a database name for most references; MLA style still requires it as part of your citation. In either case, make a note of it in case you need to retrieve it at a later date.

Common Knowledge

Things that are common knowledge do not require citation. For example:

  • Social networking sites such as Facebook allow people to communicate easily regardless of their location. (does not require citation)
  • The Japanese navy attacked Pearl Harbor on December 7, 1941. (does not require citation)

However, if someone draws an original conclusion from a common fact, then you must cite the source:

  • The ability to share real-time news and video with the world via social networking sites has emboldened student movements in countries where there is very little freedom of the press. (requires citation)
  • Japan's failure to sink any U.S. aircraft carriers in the otherwise devastating attack on Pearl Harbor assured Japan's eventual defeat. (requires citation)

Also, common sayings or proverbs need not be cited:

  • "The early bird gets the worm." (common expression with no distinct origin)

Below is a famous saying you might recognize, but it's actually from a poem by Sir Walter Scott. If you read this in a book, of course, you would cite the book. If you already knew this expression, you should still give Sir Walter Scott credit for it because it has a distinct and identifiable origin.

  • "Oh, what a tangled web we weave when first we practice to deceive."