How should you cite dead urls in a thesis? I am currently writing a thesis. In the related work part I am discussing a paper from a few years ago. The paper presents several web applications which were available back then. Hence, these applications are referenced via footnotes in this paper. Unfortunately, some applications were shutdown, hence, the URL is not working anymore.

How should I proceed, when mentioning these applications in my text? If the URLs would still be online, I would (as in the original paper) add a footnote which shows the URL + the date/time when I accessed the url. But how should I do it knowing that the URL cannot be reached anymore?

I can see two options as of now, but both don't really satisfy me:


Just do nothing, that is, no footnote whatsoever
Use an archived version of the URL from the web archive (web.archive.org) instead of the original URL. If this is a good solution, then I think it would be necessary to state in the footnote something along the lines of "due to the discontinuation of the application the original URL is down and that we provide an archived version of the URL...". If this is a good solution, I would like to know a proper formulation of the statement about why an archived version is provided.
You cite/reference stuff so later readers can check it. A dead URL is mostly useless, cite the archived one if need be (and explain why! perhaps the page went away for a reason that makes your whole point of refering to it moot...).

You mention "web application", presumably the application behind the page went away for good, in which case you don't have much to discuss anymore. Either find some detailed discussion elsewhere that covers what you are interested in, and cite that, or see if the application still exists (under another name elsewhere, a evolved version, ...) and see to cite that.