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Citing sources in APA style 6th ed.

Crediting sources and formatting references according to the style of the American Psychological Association (APA). Based on the 6th edition of the Publication Manual of the APA.

Web page / Website

Radboudumc & Werkgroep Bewegingsstoornissen van de Nederlandse Vereniging voor Neurologie. (n.d.). Misverstanden over parkinson. Retrieved from

  • If there is no year, use (n.d.), meaning "no date".
  • Only include the name of the website after Retrieved from, if this information is not part of the URL (e.g. Retrieved from ParkinsonNet: https...) but that is not the case here.
  • Only provide a retrieval date for references when the content changes over time, but that is not the case here.
  • The personal or institutional author of a webpage may also be located under an "About us" heading, as is the case in this example.
  • If there is no personal or corporate author, place the title in the author's position. 

If you refer to a complete website, it is sufficient to mention the Internet address in text without making an entry in the reference list.

On the website of the The Dutch Association of Psychologists ( . . .


Eisinga, R. N., Scheepers, P. L. H., Kraaykamp, G. L. M., & Thijs, P. (2012). Religion in Dutch Society 2011-2012 - SOCON 2011-2012 [Data guide and codebook].

  • If there is no DOI, but you do have an URL, end with: Retrieved from http://

Film on YouTube

The general format is:

Author, A. A. [nickname]. (year, month day). Title of video [Video file]. Retrieved from https://


Apsolon, M. [markapsolon]. (2011, September 9). Real ghost girl caught on Video Tape 14 [Video file]. Retrieved from

  • If there is only a nickname, put the nickname in the author's position. Without brackets.


American Psychological Association. (Producer). (2000). Responding therapeutically to patient expressions of sexual attraction [DVD]. Available from

Psychological test

For references to psychological tests, you can best follow the forms for printed or electronic books and reports. But do not use italics in the titles (the names of the tests).


Arrindell, W. A., Groot, P. M., & Walburg, J. A. (1984). Handleiding Schaal voor Interpersoonlijk Gedrag (SIG), deel I. Lisse, Netherlands: Swets & Zeitlinger.

Vegt, E. R., & Metselaar, E. E. (2011). Adaptieve Digitale Intelligentie Test [Meetinstrument]. Retrieved from

  • ​Use capitals in the name of the test, because it is a proper noun.
  • You don't have to include abbreviations in the reference.You can introduce abbreviations in text, for example:
    We used the Adaptieve Digitale Intelligentie Test (ADIT) of Vegt and Metselaar (2011) . . .  In subsequent citations in text you can then use the abbreviation ADIT.

Preprints in preprint archives

Informally published or self-archived works in preprint archives like ArXiv, bioRxiv, PsyArXiv, SocioArXiv.
Preprint versions normally precede formal peer review and publication in a peer-reviewed journal.


Grotenhuis, M. te, & Thijs, P. (2015). Dummy variables and their interactions in regression analysis: Examples from research on body mass index. Retrieved from

Thomas, E. R., Yon, D., Lange, F. P. de, & Press, C. (2020). Action enhances predicted touch. bioRxiv.

  • Check and update your references prior to publication of your own work, and refer to the final published version of sources when possible..

Working paper, individual author(s)

McMillan, M., Rodrik, D., &  Sepulveda, C. (2017). Structural change, fundamentals and growth: A framework and case studies (NBER Working Paper No. 23378).