Múltiples referencias en Beamer
\begin{frame}[allowframebreaks] \frametitle{Referencias} \tiny\bibliographystyle{plain} % style \bibliography{book_chapters,library} % *.bib \end{frame}
Fuente: tex
máx
y max
\documentclass[letterpaper,11pt]{article}
%\usepackage[english, spanish, es-nodecimaldot, es-tabla, es-minimal]{babel} % max
\usepackage[english, spanish, es-nodecimaldot, es-tabla]{babel} % máx
\selectlanguage{spanish}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\title{sample}
\author{author}
\date{\today}
\begin{document}
\maketitle
\begin{equation}
\max
\end{equation}
\end{document}