This is mainly the code
\documentclass[t,mathserif,red]{beamer}
\usepackage[round]{natbib}
begin{frame}
\citet{bla06}
end{frame}
begin{frame}
\citet{la07}
end{frame}
begin{frame}
\citet{tla08}
end{frame}
\section{Bibliography}
\begin{frame}[allowframebreaks]
\frametitle{Bibliography}
\def\newblock{\hskip .11em plus .33em minus .07em}
\nocite{*}
\bibliographystyle{elsart-harv}
\bibliography{biblio}
\end{frame}
end{document}
biblio.bib is a biblography that I have used succesfully in many papers and even in other presentation, but for this particular one it is required that the citation have the format author year. The problem is if for examle the first entry of biblio is Lucas et al, 1993 when I use plainnat or elsart-harv, beamer puts lucas et al,1993 in all citations. Looks like the only that accept is plain, but in that case the authors does not appear, others bibliographystyles does not work. Any suggestions would be greatly appreciated.
