## 5.5 Rules for referencing sources

No matter what style of quotation you use, there are a few rules you should always keep in mind.

Place References in two places: your text and in the literature list
In your text​ you consistently refer to the source you have used. This ensures that it is clear when you are using external sources and which ones they are. Do you use the same source in different places in your text? Mention the source in all these places.
What a reference in the text looks like varies per style of quotation. These are the differences you will encounter:

- In-text citation styles; in this case, the source is placed between brackets in the current text, such as (Hogeschool Rotterdam, 2019). APA is an example of an in-text quoting style.
- Numeric reference styles: in this case, ascending numbers in your text refer to the sources used, such as [2]. IEEE is an example of a numerical quotation style.
- Footnotes: for some reference styles, sources are listed in a footnote at the bottom of the page. For other styles (for example, APA), you may not use the footnote for referencing, but you may use it to give more explanation about a source.

Example: APA quoting style. A reference in the text for a source with 3 authors: (Schmidt, Deelder, & Erasmus, 2018). If you mention this source again, do it like this: (Schmidt et al., 2018)

On your literature list you must include the full source listing of all the sources you have used.

Different types of material, different rules

What your source reference looks like in the literature list differs per type of reference material. Keep in mind that a source reference for a book may therefore look slightly different from that for a video, image, or article. The number of authors of a source can also make a difference in how your reference should look. You can read what these differences are in the manual of your quotation style.