During my PhD, I wrote a couple papers referencing and using a set of notes available online, which constitute(d) the draft of a textbook (and laid down techniques and lemmata I used). [1]

Now, I am in the process of writing my thesis, and noticed that this online resource (originally title Asymptopia) had disappeared from the website of the author, which now states:

A few years ago I decided I might actually finish if I split the Asymptopia manuscript into two parts. Currently I am working on the empirical process bit, which has acquired the temporary working title MiniEmpirical. Some chapters have reached a reasonably complete form. Those chapters are in the Mini subdirectory.

In particular, the material I want to reference is gone.

Of course, this is entirely up to the author, and I have nothing to argue against this. But that does put me in a bit of a pickle, as I don’t know of any equivalent resource to cite (the exposition of the techniques was both very clear, and adapted to what I am using). I personally have a PDF copy of this resource which I saved before it disappeared, but—of course—it is not up to me to make it available.

What is the correct way to handle this? Cite the previous draft as if it were still there, possibly with a relevant link to a cached version? Something else?

[1] Bibtex entry:

    author = {Pollard, David},
    title = {Asymptopia},
    howpublished = {\url{http://www.stat.yale.edu/~pollard/Books/Asymptopia}},
    note = {Manuscript},
    year = 2003

1 Answer 1


I personally think this is not your responsibility to control the sources availability over time. If the official provider's URL is added, it's usually enough. There are numerous means to retrieve the metadata; the easiest one, as mentioned by @JeffE, is WbM, also there is Google cache.

BibLaTex supports a urldate = {YYYY-MM-DD} field, which adds "visited on MM/DD/YYYY" info to the reference in bibliography, assuring the reader which date can be used to restore access if the link is dead.

More technical aspects regarding handling external data sources with BibLaTeX are discussed on TeX.SE: URL of cited web site in bibliography

  • 4
    I am not convinced by the very first line" I personally think this is not your responsibility to control the sources availability. Surely, if I cite something that is not available to the reader, this is unprofessional -- isn't it? (If the source disappears afterwards, this is a different matter; but here we are talking of a thesis currently being written referencing a resource no longer available at the time of the writing)
    – Clement C.
    Aug 15, 2017 at 14:32
  • @ClementC. I edited the answer to underline that one must assure the source is within reach at the moment of publication. These days if something has even been put online, it is practically always reachable by various means, and it has nothing to do with the professionalism of the one who cites (again, urldate is your saver). The other thing is, if you don't trust the source anymore because it vanished in a short period of time, then you probably should get rid of it entirely.
    – andselisk
    Aug 15, 2017 at 14:40
  • I see -- thanks for the edit, esp. about the proper BibteX format!
    – Clement C.
    Aug 15, 2017 at 14:42
  • @ClementC. You are very welcomed, good luck with your manuscripts!
    – andselisk
    Aug 15, 2017 at 14:44

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