[OS X TeX] No numbers for bib items in Beamer presentation

[Christopher Menzel]

I am preparing a Beamer presentation that includes a few citations and  
am using BibTeX.  The .bbl file is being generated correctly and the  
reference numbers are showing correctly in the citations in the body  
of the presentation (e.g., "see Fitch [3]"), but I am not getting any  
numbers next to the references themselves in the bibliography.  All I  
get is a graphic -- a small icon of a document page, the sort of thing  
you often see when there's a missing graphic.  You can see what I'm  
talking about here: http://cmenzel.org/MissingNumbers.jpg .

Any info/advice appreciated.

Chris Menzel