How to Cite Encyclopedia Articles

We are sometimes asked how the encyclopedia articles can be cited. This depends on whether you want to cite the print version or the online version:

Print Version

An example for a proper citation:

R. Paschotta, article on 'optical heterodyne detection' in the Encyclopedia of Laser Physics and Technology, 1. edition October 2008, Wiley-VCH, ISBN 978-3-527-40828-3

Of course, the style of the citation may somewhat differ depending on rules of the publisher, for example.

Note that many articles of the online version are not yet contained in the print version, and the online version contains updated articles.

Online Version

When you cite an online encyclopedia article in an electronic document (e.g., on a website), the citation may e.g. look like this:

R. Paschotta, article on 'optical heterodyne detection' in the RP Photonics Encyclopedia, accessed on 2020-07-15

(Note that in 03/2019 the online version has been renamed to “RP Photonics Encyclopedia”.)

The corresponding html code (ready for copy/paste):

R. Paschotta, article on '<a href="https://www.rp-photonics.com/optical_heterodyne_detection.html">optical heterodyne detection</a>' in the <a href="https://www.rp-photonics.com/encyclopedia.html">RP Photonics Encyclopedia</a>, accessed on 2020-07-15

Code for generating an external link in Wikipedia:

== External links ==

* [https://www.rp-photonics.com/optical_heterodyne_detection.html article on optical heterodyne detection in the RP Photonics Encyclopedia]

When you cite an online encyclopedia article in a book, the citation may e.g. look like this:

R. Paschotta, article on 'optical heterodyne detection' in the RP Photonics Encyclopedia, <https://www.rp-photonics.com/optical_heterodyne_detection.html>, accessed on 2020-07-15

Better Cite the Online Version or the Print Version?

Citing the online version has several advantages:

A citation on a website or in another type of electronic document can contain a link, which allows the reader to check the cited article immediately.
The latest version of the article is available; it may have revisions which improve it over the version in the printed encyclopedia.
You do not need to have access to the print version, but only to the Internet.

On the other hand, a limitation is that an online article may be changed later on with your knowledge, or potentially even be removed. These concerns are not very serious, however:

The RP Photonics Encyclopedia is expected to stay online for many years to come.
We nearly never remove an article; at most, we would modify the article keyword, and in that case install an automatic redirection to the new article.
The date of last revision is not published, and would indeed not be very meaningful, as some revisions are strong, whereas others may be very small (e.g., changing only a single word). Instead of the date of last revision, you can simply state the date when you accessed the article.