When using BibTeX, I am happy enough adding accents where appropriate. For example
@article{key,
author="Th{\'e}venaz, Jacques",
title={Permutation Representations Arising from Simplicial Complexes},
journal={Journal of Combinatorial Theory, Series A},
year={1987},
}
However, if the above is an entry in my bib file and I use the option
\bibliographystyle{alpha}
in a LaTeX file, then this creates an error, as BibTeX naturally creates the key [Th\87] for this entry. Obviously I can go back to my bbl file and change the key here, but are there more general ways of solving this problem?

biblatex+biberallows entering directly the accents, as bibr understandsutf8. You just have to save your .bib file in utf8 format (you can do that withJabRef. – Bernard Dec 13 '14 at 01:05