I am writing a formal research paper (for a competition called National History Day), using the Chicago citation style.

I am using as a source this article. I would like to quote/reference the letter pictured in the article, and also reference some of the article surrounding it. I must sort my sources as primary or secondary. Which is this article? (I know the letter is a primary source.) Also, should I cite the letter and the article separately, or together?

Thanks; any help would be appreciated.

1 Answer 1


The letter is a primary source, as you already know. This is the actual artifact, the letter the young woman received from NASA.

The article about the history of these events is a secondary source; it's not a record of the events itself but a description. (It might actually be a tertiary source, but you could make the case for secondary.) This article explains more about primary, secondary, and tertiary sources. It's not part of CMOS but appears to be from a university that uses CMOS as its standard.

If you are using the article only to provide access to the letter, then you cite the letter while crediting the publication:

Lloyd, Jr., O. B., O. B. Lloyd, Jr. to Linda Halpern, March 13, 1962, in [... cite article here]

See "a letter found on a website" in these Chicago citation guidelines.

If you are also using the article in other ways, and not just as your source for the letter, then cite the article itself where you use it.

  • So, cite the article where it is used, and cite the letter within the article where it is used. Fabulous explanation. Thank you!
    – auden
    Mar 14, 2017 at 2:19
  • Also, I noticed while tagging my question that there were no primary-source or secondary-source tags - maybe these should be added?
    – auden
    Mar 14, 2017 at 2:20
  • @heather thanks for mentioning the tags, which I hadn't looked closely at. I made some changes there. I think that primary/secondary sources would be covered under academic-writing, but please feel free to make a proposal on meta if you think this idea should be called out with a separate tag. Thanks, and I'm glad my answer helped you. Mar 14, 2017 at 2:32
  • Thank you for your edit! That makes sense that it's covered by academic writing.
    – auden
    Mar 14, 2017 at 2:36

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