How to reference sources in an essay.

The short answer

Referencing an essay has two parts. In the text, you add a short citation wherever you use someone else's words, data or ideas, usually the author's name and the year. At the end, you give a reference list with the full details of every source you cited, so a reader can find each one.

Which style you use matters less than doing it consistently. If your teacher, exam board or competition names a style, use that one. If nobody does, pick one style, such as Harvard, and apply it the same way every time.

What needs a reference

A useful test: if a careful reader could ask “how do you know that?”, the sentence needs a reference. In practice, cite:

• Direct quotations, always, in quotation marks.
• Paraphrases and summaries. Putting an idea in your own words doesn't make it yours. If you learned it from a source, cite the source.
• Statistics and data, every time, with the organisation that produced them.
• Specific facts a reader might not know or might doubt, such as the date a law came into force or the result of a study.
• Distinctive arguments or frameworks that came from someone else, even if you go on to disagree with them.

You don't need to cite common knowledge (water boils at 100°C at sea level; the Second World War ended in 1945) or your own reasoning. Your argument, your judgements and your conclusion are yours, and they shouldn't carry a citation. If you are unsure, cite it: a missing reference can look like copying.

In-text citations and the reference list

In-text citations

In an author-date style such as Harvard, the citation goes in brackets at the point you use the source, before the full stop:

Putting the author in your sentence reads better when the source's view is what you are discussing. Add a page number when you quote, or when you point to one specific part of a long report.

The reference list

At the end, under the heading “References”, list every source you cited, in alphabetical order by author or organisation. Each in-text citation should lead to exactly one entry, and every entry should be cited somewhere in the text. A list of things you read but didn't use is a bibliography, which most short essays don't need.

Which referencing style to use

There are many styles. These are the ones school students meet most often:

If you have a free choice, Harvard is a sensible default: it is short in the text, widely understood and easy to apply to websites and reports. There is no single official version of Harvard, so small differences in punctuation between guides are normal. Many UK universities follow the version in Cite Them Right, which the examples below use. What matters is that you stay consistent within one essay.

Examples for the sources you will use

Most guides start with books. For an essay about current or future issues, you are more likely to use web pages, reports and data. These are the Harvard patterns for each, with the in-text form after it.

Record the details when you find the source, not at the end; the guide to finding evidence explains how to keep a running list. For online sources, note the date you accessed them, because pages change.

When details are missing

Online sources often lack something. The usual fixes:

• No named author: use the organisation that published it, such as a government department or a charity. If there is no organisation either, use the title, and ask whether the source is reliable enough to use at all.
• No date: write “no date” in place of the year, for example (Organisation, no date). Some styles use “n.d.”.
• No page numbers: leave them out. Web pages don't need them. For a long PDF report, use the page number printed on the page you mean.
• Two sources by the same author in the same year: add a letter, such as (Organisation, 2025a) and (Organisation, 2025b), and use the same letters in the list.

If you found a figure in one source that quotes another, cite the original where you can, after checking it says what you claim. If you truly can't reach the original, say so: “(Original author, Year, cited in Source you read, Year)”.

Referencing in a plain-text box

Many competitions and online applications ask you to paste your essay into a form that doesn't allow italics or footnotes. Author-date styles survive this well. Write the citations in brackets as normal, put the reference list in the references field if there is one (or at the end of the text if not), and include full URLs so the reader can click through.

Check whether references count towards the word limit. In many essay competitions they don't, but the rules for each one will say.

Common mistakes

1. Citing where you searched, not what you read.“Google”, “the internet” and “BBC website” are not references. Cite the specific page, with its author or organisation, title and date.
2. Citing an encyclopedia instead of its source.Use Wikipedia to find sources, then read and cite the source it relies on.
3. A bare link in place of a citation.A URL in brackets tells the reader nothing about who said what. Put the author and year in the text, and the URL in the list.
4. References you haven't read.Only list sources you have opened and checked. A citation is a claim that the source says what you say it does.
5. Mixing styles.Copying references from different places gives you three formats in one list. Pick one and convert them all.

The stronger version names who found it, gives the reader a way to check, and shows you read the source carefully enough to notice its limits. That is what referencing is for, and it is one of the clearest signs of how well you have built each paragraph on evidence.

Reference generators and AI

Free reference generators and the citation buttons in Google Scholar and many library catalogues can save time. Check every result against the source, because they often get author names, dates and capital letters wrong, and they can't tell you whether you have the right edition.

Be much more careful with AI chatbots. They can produce references that look real, with plausible authors, titles and links, for sources that don't exist or don't say what is claimed. Never put a reference in your essay that you haven't opened and read yourself. Schools and competitions increasingly set rules on this: Ten Years From Now's AI-use policy, for example, allows AI for finding sources you then check, but not for generating references you haven't read.

Further reading

These university guides go into more detail on each style. They are written for university students, but the patterns are the same for a school essay.

• Quick guide to Harvard referencing (Cite Them Right), The Open University Library
• MLA Works Cited: electronic sources, Purdue Online Writing Lab
• Citing sources, The Writing Center, University of North Carolina at Chapel Hill

Try it on this year's questions

Ten Years From Now is a free essay competition for students aged 14–18, anywhere in the world. Choose one of three questions and make an evidence-based case in up to 1,000 words, judged against six published criteria, including how accurately you use and cite evidence. References don't count towards the word limit. Round 1 closes on 28 February 2027 and Round 2 on 15 June 2027.

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