\documentclass[11pt]{article}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amsthm}
\usepackage{graphicx} 
\usepackage{epsfig}

\topmargin     -.3cm
\textheight     22cm
\textwidth      14cm
\evensidemargin  1.1cm
\oddsidemargin   1.1cm

\newtheorem{lemma}{Lemma}[section]
\newtheorem{theorem}[lemma]{Theorem}
\newtheorem{corollary}[lemma]{Corollary}
\theoremstyle{definition}
\newtheorem{example}[lemma]{Example}
\newtheorem{definition}[lemma]{Definition}

\makeatletter
\def\keywords{
    \vspace{1ex}
    \noindent
    \if@twocolumn
      \small{\bf  Keywords}\/---$\!$    \else
      \begin{center}\small\ {\bf Keywords}\end{center}\quotation\small
    \fi}
\def\endkeywords{\vspace{0.6em}\par\if@twocolumn\else\endquotation\fi
    \normalsize\rm}
\makeatother

\bibliographystyle{plain}

% ------------------------------------------------------------------------




\begin{document}

\title{Title}

\author{author I, 
author II, 
author II,
author III\thanks{corresponding author}, 
author IV.}
\date{~}

\maketitle

\begin{abstract}
Here you write an abstract, with a maximum of about 100 words.
\\ \\
{\sc Keywords:} give some keywords
\end{abstract}

%--------------------------------------------------------------------------



\section{Introduction}
The text is separated into sections. Start with an introduction, more follows
later.

\section{Second section}
Each section may be separated into subsections, and can contain figures.
All standard latex commands may be used, including those from the packages
listed above in the preamble. Please avoid using other packages and own definitions
and if you do, put them in the preamble.
 
\section{A bibliography}
The bibliography can be made with the thebiliography command as below.






% ---------------------------------------------------------------------
% This is the file swiexample.bbl:
\begin{thebibliography}{10}
\bibitem{ref1}
author, \& author,
\newblock {\em  journal} {\bf volume},
\newblock page-page, year.

\bibitem{ref2}
author, \& author,
\newblock {\em  journal} {\bf volume},
\newblock page-page, year.

 \end{thebibliography}
% ---------------------------------------------------------------------
\end{document}