Plagiarism is the copying of data from someone else’s work without a correct acknowledgement of the source and in such a way that it is presented as your own work. This is considered fraud. Plagiarism breaches the basic principles of copyright law and the ALLEA code; the European Code of Conduct for Research Integrity. In this guide we explain how you can prevent plagiarism.

How to prevent plagiarism?

Preventing plagiarism is fairly simple in theory; clearly and traceably state the original source  for the quotation that you included in your work. You can do this as follows:


You have literally copied someone else's text. The text is written between inverted commas and the source is acknowledged correctly. For more information on quotation, read The APA Guidelines explained.


You include ideas or texts from another author in the text in your own words. The correct acknowledgement of the source is also mandatory in this case.


You refer to the ideas, methods or findings of others with the correct acknowledgement of the source.

How do you acknowledge your sources correctly?

A correct acknowledgement of the source is the best way to prevent plagiarism. In this way, you clearly demonstrate the origin of the material used. You do this by giving a number of details, such as the author’s name, title, year and publisher. For digital sources you also give the name of the website and the date it was consulted. You can find a practical guide for the acknowledgement of sources in higher education in the guideline The APA guidelines explained.

Citation style

The way in which the acknowledgement of sources must be recorded, relates to the (mandatory) citation style. Each subject field uses one or several fixed citation style(s). Two examples of citation styles are the commonly used APA style of the American Psychological Association and the Guidelines for Legal Authorsof Wolters Kluwer publishing. For more information about the APA style, see The APA guidelines explained.

Reference management

In order to be able to store bibliographic references correctly, many higher professional educational institutions and research universities make reference management software such as EndNote or RefWorks available.

Other useful programs include Mendeley or Zotero. Both are free to use. Keeping a reference list is also possible in Microsoft Office Word. Another simple way to apply APA, is by using a so-called APA generator, for instance the one provided by Scribbr.

Quoting from your own work (e.g. self-citation)

From a copyright perspective, there should be no problem not to acknowledge the source when quoting from your own work. However, this is not the case within the world of academic research: if you do not acknowledge the source, you will be plagiarising your own work.

According to the Dutch code of conduct for Research Integrity’ (KNAW, NFU, NWO, TO2-federation, Netherlands Association of University Colleges and the Association of Universities, 2018) there must always be a correct acknowledgement of the source. According to researchers, this also means that correct acknowledgement of the source is done for your own earlier publications, also called self-citation.

In April 2014, the KNAW Citation Committee drew up the Correct citation advisory letter to provide more clarity concerning the correct reuse by the creator of texts and research results that had already been published by themselves. The recommendation provides greater clarity concerning the meaning of the concept of ‘self-plagiarism’ in research. Testing frameworks are also provided concerning what is and what is not permissible when reusing material previously published by the academic research author himself. This tool is used in the assessment of specific cases.

Questions? get in touch with your Copyright Information Point (AIP)

Do you have further questions about this quick reference guide? Please contact one of the members of staff at the Copyright Information Point (AIP) of your institution.


Download deze vuistregels in PDF
Vuistregels plagiaat
Download Dutch, File extension: PDF (File size: 64 KB)
Download this quick reference guide in PDF
Quick reference guide on plagiarism
Download English, File extension: PDF (File size: 40 KB)