\documentclass[a4paper,11pt]{article}
\input{configs.tex}
\begin{document}
\input{title.tex}
\newpage
\tableofcontents
\thispagestyle{empty}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\newpage
\section{Introdução}
\section{Section 1}
\section{Section 2}
\section{Section 3}
\section{Conclusão}
\newpage
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%to insert references
\nocite{ams}
\addcontentsline{toc}{section}{Referências}
\renewcommand\refname{Referências}
%\bibliographystyle{abntex2-alf}
\bibliographystyle{plain}
\thispagestyle{empty}
\bibliography{referencias}
\thispagestyle{empty}
%\listoftodos
%Example text \todo{Mude aqui} and more text
%\listoftodos[List of suggested changes]
\end{document}