\documentclass[11pt]{article}
 
  \newcommand{\sm}{\smallskip}
  \newcommand{\ms}{\medskip}
  \newcommand{\bs}{\bigskip}
  \newcommand{\Title}[1]{{\large\bf \uppercase{#1}}}
  \newcommand{\Keywords}[1]{\smallskip \noindent \textbf{Keywords:} #1.}
  \newcommand{\MSC}[1]{\smallskip \noindent \textbf{AMS Subject Classification:} #1.}
  \newcommand{\Email}[1]{\\
    \smallskip \small\textbf{e-mail:} \textnormal{#1}}
  \newcommand{\Author}[2]{{\sc #1} \\
    \medskip
    {\small\it #2}}
  \renewenvironment{abstract}{\noindent}{}    
  
\begin{document}
 %% Please leave the blank lines in the document.
 \begin{center}
  \Title{Title of the talk}
  
  
  % If there is more than one author, than the speaker should be underlined.
  % Below we have an example, when the affiliation of all authors is the same.
  % The example includes the usage of the footnote.
%    \bs
%    \Author{John Smith, Alice Rice and \underline{Ann Beck}\footnote{Research supported in part by ...}}
%      {Faculty of Mathematics Computer Science and Econometrics\\%    
%      University of Zielona G\'ora}
%    
%    \Email{John@wmie.uz.zgora.pl, Alice@wmie.uz.zgora.pl, Ann@wmie.uz.zgora.pl}
  
  % In case when the affiliation of some authors differ, please use the following schema.
    \bs
    \Author{John Smith}
     {Faculty of Mathematics Computer Science and Econometrics\\
     University of Zielona G\'ora}    
    \Email{John@wmie.uz.zgora.pl}
    
    \ms
    \Author{Alice Rice and \underline{Ann Beck}}
     {Faculty of Mathematics\\
     University of Brenn}    
    \Email{Alice@brn.pl, Ann@brn.pl}
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \end{center}
 \ms
 
 \begin{abstract}
 Here should be the body of your abstract. The abstract should be limited to one page. 
 \end{abstract} 
 
 \Keywords{keyword1, keyword2, keyword3}
 
 \MSC{05C69, 05C05}
 
 \ms
 \begin{thebibliography}{99}
  \bibitem{BDH2007} R.C. Brigham, R.D. Dutton and S.T. Hedetniemi, {\it Security in
  graphs}, Discrete Appl. Math. {\bf 155} (2007) 1708--1714.
  
  \bibitem{CH} M. Chellali and T.W. Haynes, {\it Global alliances and independence in
  trees}, Discuss. Math. Graph Theory {\bf 27} (2007) 19--27.
  
  \bibitem{KHH2004} P. Kristiansen, S.M. Hedetniemi and S.T. Hedetniemi, {\it Alliances
  in graphs}, J. Combin. Math. Comput. {\bf 48} (2004) 157--177. 
 \end{thebibliography}
 
\end{document}