[OS X TeX] bibtex question

["M. Tamer Özsu"]

I have an interesting problem that I have not been able to resolve. I  
have the following entry in my .bib file that gives me an error when I  
run it with alpha style:

@article{alg:syn:952,
	Author = {Guillaume Br\`es},
	Journal = tsi,
	Number = 5,
	Pages = {341--354},
	Title = {Panorama sur le G\'{e}n\'{e}raux Byzantins},
	Volume = 10,
	Year = 1991}

Latex complains:

! Undefined control sequence.
<argument> Br\9
                1
l.1659 \bibitem[Br\91]{alg:syn:952}

When I ask it to continue, it generates an entry with the citation  
label [Br1]

When I run it with plain or abbrv, it works correctly.

Would anyone have a suggestion? Thanks.

==Tamer