\documentclass[10pt]{paper}
\usepackage{graphicx,amssymb,hyperref}
\usepackage[a4paper,top=1cm,bottom=2cm]{geometry}
\begin{document}
\pagestyle{empty}


%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%
\begin{center}
\textsl{ {\LARGE }}\\ \bigskip
\Large{\bf{Title of your Astract}}\\

%\line(1,0){300}\\
\end{center}
%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%

%%% name and institution of authors
\begin{center} 
\Large{Name Surname}\\
{\small Address}
{\small  \tt email address}\\
\Large{Nome Surname Coauthors}\\
{\small address }
{\small \tt email addres}
\end{center}

%Poster or Oral Presentation
\Large{Indicate if the abstract is for Poster or Oral Presentation}\\

WRITE HERE YOUR ABSTRACT -Please do not exeed one page

\noindent

{\small
\begin{thebibliography}{99}

\bibitem{bib1} Authors
\newblock {\em Title }, 
\newblock {Journal/book information}

\bibitem{bib2} Authors
\newblock {\em Title }, 
\newblock {Journal/book information}


\end{thebibliography}
}


\end{document} 