[comp.text.tex] Multiple ref footnote in LaTeX - how?

drstrip@intvax.UUCP (David R. Strip) (11/19/90)

I would like to cite several references via footnotes in a
book style latex document. I would like the output to have
superscript type footnote indices seperated by comnas, 

For example:

It is well known that^{1,2,3}

where the ^ indicates that the following group appears as a superscript.

I have tried various permutations of the footnote commands in LaTeX, but
none seem to give the comma. If I give just the \footnote commands one
after another, I get a list of indices with no commas. If you put
a comma between the entries, the comma is not part of the subscript.
If you use the footnotemark and footnotetext commands, you cannot give more
than a single number in the footnotemarkcommand.

I am at a loss as to what to try next. This seems like a fairly typical
citation style, so it does not warrant the answer that the style file
is correct for all uses.

Thanks in advance for any suggestions.
drstrip@cs.sandia.gov