\documentclass[11pt]{article}
  \newcommand{\Title}[1]{{\large\bf \uppercase{#1}}}
  \newcommand{\Email}[1]{\\
    \smallskip \small{e-mail:} \textnormal{#1}}
  \newcommand{\Author}[2]{{\sc #1} \\
    \medskip
    {\small\it #2}}
  \renewenvironment{abstract}{}

\begin{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.
    %   \bigskip
    %   \Author{Anna Kowalska, \underline{Jan Nowak} and Piotr Szulc}
    %   {Gda\'nsk University of Technology}
    %
    %   \Email{kow@mif.pg.gda.pl, now@mif.pg.gda.pl, szu@mif.pg.gda.pl}

% In case when the affiliation of some authors differ, please use the following schema.
    \bigskip
    \Author{Anna Kowalska}
     {Gda\'nsk University of Technology}
    \Email{kow@mif.pg.gda.pl}

    \medskip
    \Author{\underline{Jan Nowak} and Piotr Szulc}
     {University of Gda\'nsk}
    \Email{now@univ.gda.pl, szu@univ.gda.pl}
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    \end{center}

\medskip

    \begin{abstract}
    Here should be the body of your abstract. The abstract should be limited to one page.
    \end{abstract}

\medskip

    \begin{thebibliography}{99}
    \bibitem{HHHK}  T. W. Haynes, S. T. Hedetniemi, M. A. Henning, and D. Knisely, Stable and unstable
    graphs with total irredundance number zero. Ars Combinatoria 61 (2001), 33--46.
    
    \bibitem{HH} T. W. Haynes and M. A. Henning, A characterization of diameter-2-critical graphs
    with no antihole of length four. Central European Journal of Mathematics 10(3) (2012),  1125--1132.
        
    \bibitem{HY} M. A. Henning and A. Yeo, Total domination and matching numbers in graphs with
    all vertices in triangles. Discrete Mathematics 313 (2013), 174--181.
    \end{thebibliography}

\end{document} 
