Skills Earth Sciences

Paraphrasing and citation methods/referencing

Using work done in the past is essential for the progress of science. Obviously, you don’t have to reinvent the wheel every time again. There are two ways to cite other sources in your own work:

If you want to use ideas/results/conclusions from other texts but you write them down in your own words, you are paraphrasing. Paraphrasing is a very useful way to summarize other work(s) in a condensed manner. It is the most often used method in Earth Sciences to refer to previous work. There are three conditions that should be met for a good paraphrase:

  • The source is known and referred to correctly (for referencing, see below).
  • The paraphrased text is really in your own words (and not just the word order mixed). If you want to copy the exact words of a text, you should quote (see below) rather than paraphrase.
  • Make sure that it is clear where you paraphrase another text and where your own ideas are stated.

When you want to use the same words or sentences from another source, you must quote these words by putting quotation marks at the beginning and end. Although not very common in geosciences, it is still very important to know the conditions that should be met to quote correctly:

  • The source is known and referred to correctly (for referencing, see below)
  • The quote is literally copied from the source text – you cannot change words or the word order. Sections can be omitted using […] in-between if the integrity of the quoted idea is maintained.
  • A quote can only be a small part of your text. Although there are no strict rules on how large a quote may be, a rule of thumb is that for each sentence you quote, you have to wright two sentences yourself to elaborate on the quote used.
  • Don’t take a quote out its context. For example, a quote from an ironic text cannot be used as a serious argument in your own text.


See Using sources – Citing – LibGuides at Utrecht University ( for more information.