In its most elementary definition plagiarism is taking someone else’s work, words or ideas, and presenting it as your own – whether intentionally or unintentionally. By properly referencing your sources, you show your reader where the information has come from and clearly distinguish your own thoughts from those of others. When something is considered common knowledge you do not need to cite a source. 

The most common way to integrate other people’s ideas in your own writing is to paraphrase. This means putting ideas and text into your own words, while still retaining the original meaning and intent. By paraphrasing, you show you have understood the source well and are able to relate it to your own research. When you paraphrase, you must always provide a reference to the original creator of the idea. 

An example of what a paraphrase looks like (in APA style):
The digitization of (scientific) archives has allowed for previously invisible materials to become widely visible, findable and accessible (Volynskaya, 2025).

When you quote, you copy a text word-for-word from the source. Quoting is useful when the precise wording is significant. You should, however, use quotes sparingly. When including quotations, ensure you convey the original source's intent, as well as making clear how it relates to your own work. A quotation starts and ends with quotation marks or it can be formatted as a block quote. You must always provide a reference to the original source.

An example of what a quotation looks like (in APA style):
“Within the digital archive, the vestiges of science – along with many other forgotten fragments – are brought into view, made visible as never before” (Volynskaya, 2025, p. 10).

There are many different citation styles. What citation style you use, depends on the discipline you are in and whether you are writing for a specific publication (for example, Nature). Common styles are APA, Chicago, and MLA. Some of these styles will have in-text references, while others will use foot- or endnotes to reference sources.

• This is an in-text reference (Johnson et al., 2014).
• This is a footnote reference.¹
  —
  ¹ Example Johnson, Reference Examples (Leiden University Press, 2020), 35.

Online resources such as Cite Them Right provide support in correctly referencing different sources using your chosen citation style. 

It is not only necessary to know how to clearly reference other people’s work; it is also useful to be able to recognize basic elements of citations. This way, you can quickly identify core details about the source and make a first judgement about the usability of the source for your research.

Watch the video below to see what elements a citation is built of and how to use this citation information.

The more sources you use, the more time-consuming it becomes to organise these sources and manually insert the correct references into your work. Luckily, reference manager software helps you save, organise, and generate references.

Want to know more? Take a look at the webpage on Reference Managers.