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Citing your sources

A citation is a reference to the source, including the page number of the original text (or comparable marker for unpaginated electronic texts). Citations can be given in different forms, including footnotes, endnotes, and in-text references. The different forms for correct citation are discussed later in this section.

If you do any of the following three things in your paper, then you must provide a citation:

  1. Quote a source verbatim: Whenever you reproduce the exact words of another author, you must surround them with quotation marks (or, for longer quotations, use indenting to create a block quote).
  2. Cite a distinctive idea: When you paraphrase an author's interpretation (i.e. present it in your own words), you should still acknowledge the source if you are paraphrasing an insight or analytical point rather than a straightforward matter of fact.
  3. Cite facts that are not widely known or that might be contested: In some cases, even facts should be cited and attributed to a source. If a source provides you with information that you could not have readily found elsewhere, or that might be challenged, cite it, even if you paraphrase the author's words. This is especially important when the facts are controversial.

The examples below will help you better understand these conditions.

Examples: When do you need to cite this source?

Take a look at the passage below, from an internet biography of Martin Luther. This passage will be the source paragraph for all of the examples below. We will consider how you might make proper use of the source in your paper in each of the three instances given above.

Original Source:
In July of 1505, Martin was caught in a horrific thunderstorm.  Afraid that he was going to die, he screamed out a vow, “Save me, St. Anna, and I shall become a monk.” St. Anna was the mother of the Virgin Mary and the patron saint of miners. Most argue that this commitment to become a monk could not have come out of thin air and instead represents an intensification experience in which an already formulated thought is expanded and deepened. On July 17th Luther entered the Augustinian Monastery at Erfurt.

Source: David M. Whitford, "Martin Luther," Internet Encylopedia of Philosophy,

Here are three different ways that you might make use of this source paragraph by David Whitford in your own paper. Note that each one of them requires you to cite Whiford's article, each for a different reason:

1. Direct quotation

You write:
Luther decided to become a monk in 1505, just a few days after being "caught in a horrific thunderstorm" and taking a vow to St. Anne.

Your quotation is short -- only five words -- but it is a direct quotation from Whitford. There are many other ways to describe this event, but you chose to use Whitford's language instead of paraphrasing, so you must attribute it to him.

2. Citing a distinctive idea

You write:
Luther became a monk after he survived a frightening thunderstorm in the summer of 1505, having made a vow to St. Anna. But many of Luther’s biographers think that he would probably not have made this commitment if he had been not already been considering the monastic life for some time before that.

Here you have successfully paraphrased the source and avoided using the author's own language. But you are still citing a distinctive interpretation about when and why Luther made up his mind to become a monk. You must tell the reader where you learned that "many of Luther's biographers" think this. If you do not include a citation, you are suggesting (even if unintentionally) that you have read many biographies of Luther and are drawing this conclusion on the basis of your own reading. That is dishonest.

3. Citing facts that are not widely known or may be contested:

You write:
Finding himself outdoors in a fierce summer rainstorm and fearing for his life, Luther took a vow to St. Anne; he begged her to save him, and promised that if she did so he would enter a monastery.

Again, you have successfully paraphrased the source and avoided using the author's own language. Here you are citing what appears to be more of a fact than an interpretation; you are just telling the reader what Luther said. But this "fact" may still be subject to dispute and may not be common knowledge. The story is widely told, but how do we really know it is true? With "facts" like this that depend on the reliability of the sources, it is always advisable to cite your sources.

Citation NOT needed: Widely known facts:

You write:
Martin Luther became an Augustinian monk on July 17, 1505.

In this case, you do not need to cite Whitford. This fact is widely known and can easily be corroborated. Of course, it is not always easy to know what facts are "widely known" when you are not an expert, so when in doubt, cite the source. No reasonable person will penalize you for citing too often.