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MLA 9 Workshop: When to Cite


These categories do not require a citation:

  • your own thoughts (but be careful that you are differentiating between your own thoughts and what you have read)
  • common knowledge (MLA 4.13)
  • passing mentions (MLA 4.14)
  • allusions (MLA 4.15)
  • epigraphs (MLA 4.16)

Everything else requires a citation. Every time you

  • quote,
  • paraphrase or
  • summarize

a source, include an in-text citation.

It is better to have too many citations than too few. If a citation is necessary and not present, it is plagiarism. If in doubt, CITE!

Common Knowledge

Facts that are well-known and not widely disputed.

·    Generally you can consider something common knowledge if you can find it in 5 different reference sources.

·    Many historical, geographic and scientific facts are considered common knowledge.

·    What’s considered common knowledge may also change based on your audience.

  • Halloween is celebrated on October 31st.
  • Disney World is located south of Orlando.
  • C is the chemical symbol for carbon.
  • Joe Biden is the president of the United States.
  • Havana is the capital of Cuba.


Which of the following are common knowledge?

  • President Trump was elected in 2016.
  • President Trump is the most significant president of the last fifty years.
  • President Trump’s approval rating was 39% in March 2018.
  • O is the chemical symbol for oxygen.
  • Oxygen is one of the most abundant elements in the universe.
  • The moons of Saturn are surrounded by oxygen and may be able to support life.
  • Polar bears are an endangered species.
  • Polar bears’ black skin absorbs sunlight and keeps them warm.
  • Polar bears can swim up to 80 km at a time without stopping.
  • The Great Depression started with the stock market crash of October 1929.
  • The unemployment rate during the Great Depression was 24.9%.
  • Franklin Roosevelt helped to lift the country out of depression by creating work relief programs such as the Civilian Conservations Corps and the Works Progress Administration.

West Campus Librarian

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