Citing supplementary material as a reference? I am about to submit a paper to https://www.siam.org/Conferences/CM/Main/sdm19 (deadline is today) and I have supplementary material contains further evidence, proofs, examples and the like.

I want to reference my supplementary material, like this:


  ... however, we found that the runtime is polynomial [24] and that ...


and then in the references:


  [24] A. Uther, This One Paper - Supplementary material. www.github.com/asdf/wer


I found no guideline regarding this. Can I simply put my reference material on a website (e.g. github), put the link into the References section and cite the reference in the text? I have not seen this in any other paper, but I want to cite the supplementary material several times and using a footnote might be confusing: If I put the footnote at the first page I need to cite (e.g. page 3) and I need to cite it at page 9 the last time, people will be confused where to find this footnote.

Note: The conference is NOT double-blind, but only single-blind. (I don't know their names, but they know my name.)
Usually (with journals that make supplementary material available via the article web page), I'd say "see supplement[ary material]" or refer to figures as "Fig. S23" or the like.
As you comment that the journal will not make the supplementary material available, I'd suggest to publish in a repository like arXiv or Zenodo and then refer to that location. Still making clear that this is supplementary material to your paper, e.g. "see supplementary material [24]".
Or state at the beginning of the paper that supplementary material is available externally, give the location there (as opposed to in the references) and then refer to it as supplementary material like you'd do for "normal" supplements.