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Citing Sources

Tips on citing sources from the DI Library

What Is Plagiarism?

Plagiarism is turning in someone else’s work, in any form, as your own. Plagiarism is also turning in your own work for another assignment.

Using someone else’s words or ideas without citing the source implies that those words or ideas are your own.

  • This includes words and ideas from any source – magazines, books, newspapers, songs, TV programs, movies, web pages, blogs, charts, diagrams, emails, Facebook updates, etc.

Plagiarism is also:

  • Including incorrect information in a citation
  • Making up a citation
  • Citing a source other than the one you used

You can even plagiarize your own work. Once you have turned in a paper or project for a grade, you can’t turn that same work in again for a new grade in a different class, unless you have explicit permission from both instructors.

Remember: “I didn’t mean to!” isn’t an excuse.


Common knowledge

Facts that “everyone knows” are considered common knowledge. You don’t need to cite a source for common knowledge.

  • The fact that Frank Lloyd Wright was an architect is common knowledge; you don’t need to cite your source when you say this.

If you find a fact without a citation in at least three reputable sources, it is probably common knowledge.

  • If you’re not sure, cite your source to be safe, or ask your instructor.


Not sure what counts as plagiarism?

Learn more about plagiarism and how to avoid it in this interactive tutorial:


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Avoiding Plagiarism

To avoid plagiarism:

  • Quote your sources correctly
  • Paraphrase or summarize your sources correctly
  • Cite every source correctly


Quote correctly

When you want to use the exact words of someone else, use a quotation. For short passages, use quotation marks at the beginning and end of the quotation. For longer passages, use block quotes. At the end of the quotation, add an in-text citation. Don’t forget to include the page number (if there is one).


Paraphrase and summarize correctly

When you want to use someone else’s idea but put it in your own words, paraphrase or summarize. To paraphrase or summarize an idea, you need to condense or clarify that idea. It’s not enough to take someone else’s sentence and replace some of the words; you need to truly understand the idea and state it in a new way. At the end of your paraphrase or summary, add an in-text citation. Don’t forget to include the page number (if there is one).


Cite every source correctly

Every time you use someone else’s words, ideas or images, cite your source. EVERY time. Make sure to match the correct source to each quotation, paraphrase or image.


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