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Universiteitsbibliotheek – LibGuides

Citing: Using sources

Using sources in your text

When writing your own text you will (almost) always use the work of others.There are three ways in which you are allowed to incorporate the work of others into your own work:

  1. quoting
  2. paraphrasing
  3. summarizing

In each of these cases you need to refer to the original work of the original author (your 'source').

It does not matter where the information originates from: a scholarly journal, a thesis, conference proceedings or directly from the internet.

If you reuse material without citing the source you are committing plagiarism! This may have serious consequences.

Why it is important to cite your sources

Referring to your sources correctly and in the right places increases the readability and verifiability of your publications.

  • By mentioning your sources correctly and completely, you make clear which information you have taken from other authors and where your readers can find the original information. This way they can check whether you have referred to the information correctly.
  • Correct citing contributes to the transparency of scientific communication and the prevention of plagiarism
  • You also make clear to the reader how your publication relates to other publications in the same field and you point out publications that could be of interest
  • And by acknowledging your sources you give credit to the original author(s).

Copy literally: quoting

Quoting is to copy verbatim from a text in a publication (a quote).

Conditions of quoting
Quoting is allowed, provided that the following conditions are met:

  • The source is stated correctly
  • The quote is copied word for word (no changes or translation)
  • Beginning and end of the quote are clearly indicated (for example by using quotation marks)
  • The quote is relevant to your argument and is only a small part of your text. A quote is not meant just to embellish your publication

For what do I use  quotes?
You use quotes to illustrate your point or if you want to analyse the original phrasing of somebody else.

What do I have to bear in mind when quoting?
You are not allowed to use quotes as a replacement of your own text. This means that a paper may never consist of quotes pieced together. This is plagiarism, even if you do refer to the source. Please be aware that you do not take the quote out of its original context. For instance, it must be made clear if the quote is meant ironically. So always quote in accordance with the original intentions of the original author.

How much text can I quote?
How much text you can quote depends on the purpose of the quote and the length of the source text. Sometimes one line is enough, another time a whole paragraph is needed. Rule of thumb: for each cited line, write two lines yourself in which you elaborate on the quote.

Use your own words: paraphrasing and summarizing

Putting into your own words passages from the text of others, is called paraphrasing. Here you try to retain the meaning of a passage from the original text without literally copying the text in question (as you do in quoting). 

In paraphrasing it is very important that you use your own words to describe the ideas of others. Merely changing a few words, or the order of the sentence is not enough. This will also be considered plagiarism. In that case it is better to copy the text word for word (=quoting), followed by your own ideas.

In a summary you give a brief overview of the content or the main ideas from (part of) a source. Summarizing means you present the most important and relevant information from your source in your own words. A summary is (usually) substantially shorter than the original text.

Paraphrasing and summarizing are allowed, provided that you meet the following conditions:

  • state the source correctly
  • indicate clearly which part contains your own ideas and which is the part you have copied


Plagiarism is reusing material without mentioning your sources, and as a result making it look like your own work. Paraphrasing/summarisng without mentioning your sources is a form of plagiarism.

What you need to know about plagiarism:

There are rules you need to follow if you use the work of others in your own work. Read below what you must do to avoid plagiarism.

What is plagiarism?

Plagiarism is reusing material without stating sources, making it look like your own work. Paraphrasing/summarising without stating your sources is a form of plagiarism.

Utrecht University considers any form of academic dishonesty to be a very serious offence. Utrecht University expects each student and staff member to be familiar with and to observe the norms and values that ensure academic integrity.

How you practise science correctly is recorded in several codes/rules of conduct, for example The Netherlands Code of Conduct for Scientific Practice (VSNU)

When students are suspected of plagiarism sanctions may be implemented.



How do I prevent plagiarism?


5 tips to prevent plagiarism:

  1. Always refer to the sources that you have used and take the time to state them correctly and consistently
  2. Use quotes: clearly recognisable as a quote and including a correct reference
  3. Paraphrase: reformulate the text in your own way and try to avoid using the same words too much. Do this without changing the meaning of the idea itself. Also don't forget to refer to the original source here!
  4. Present your own thoughts and ideas. Prevent self-plagiarism, which can arise if you copy your own previous work!
  5. Use a plagiarism checker

More about plagiarism

You can commit plagiarism in many ways. Some forms of plagiarism seldom occur, others occur frequently. Some are more serious than others.

A special way to commit plagiarism is to include sections of text originating from writings of which you are the (co)-author without stating the source. This is also known as self-plagiarism, even though that term is misleading. In many cases self-plagiarism is not allowed and it is always contrary to the principles of academic integrity.

Sometimes including sections of texts are to be disapproved of, even though the sources are referred to, for instance if you include or paraphrase large sections, or if these included sections take up a large part of the new publication (in size or importance).

There are also offences which have nothing to do with plagiarism, but are serious nonetheless, such as excessive self-citation, in which you refer to your own writings, not because it benefits the text but because you want to increase your citation scores

Referring to your sources