How to cite sources

Citing sources is how you give credit and let readers verify your work. It is not a formality — it is the backbone of honest academic and factual writing.

What it is

A citation tells the reader where a fact, idea, quote or statistic came from. It appears in the text (in-text citation) and in a full list at the end (references or bibliography). The exact format depends on the style you are using.

Why it matters

It goes hand-in-hand with avoiding plagiarism, lets a reader check your claims, and shows the sources you built your argument on. Missing or wrong citations undermine credibility.

The common styles

• APA (psychology, education, social sciences): in-text "(Smith, 2020)" and a "References" list.
• MLA (literature, humanities): in-text "(Smith 23)" and a "Works Cited" list.
• Chicago (history, many humanities): either author-date in text or footnotes, with a bibliography.
• Harvard (common in business and many UK institutions): author-date like APA, with a reference list.

Pick the style your field or publication requires and apply it consistently.

How to cite in text

For a direct quote, use quotation marks and a citation with a page number if available. For a paraphrased idea (restated in your own words), cite the source but no page number is usually required. Always cite the idea's origin, not just direct quotes.

What to include in a reference

For a book: author, title, publisher, year. For a journal article: author, title, journal, volume, pages, year. For a webpage: author or site, title, site name, date, URL. Exactly which parts and the order depend on your style — follow the guide for your field.

How to build a reference list

List every source you actually cited, in alphabetical order by author. Do not list sources you did not use. Keep the style's exact punctuation and italics rules consistent.

How to avoid common mistakes

Do not cite a source you did not read (secondary citation — if you read it quoted somewhere, say "as cited in"). Do not use a citation tool you have not checked. Do not drop citations you are unsure of. Use an identifier like a DOI or URL so the reader can find the source.

Practical tips

• Record every source's details as you use it, not at the end.
• Keep a reference manager or a simple note file.
• Double-check the specifics of your style before submitting.

Checklist

• I used the style my field or publication requires.
• I cited every direct quote and paraphrase.
• My in-text citations match my reference list.
• I only listed sources I actually used.
• I included enough to find each source (author, year, and DOI/URL/page).
• I applied the style consistently.