%%%
%%% Modify appropriately only the text between \begin{document} and \end{document}.
%%%

\documentclass[11pt,twoside]{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsthm} 

\usepackage[hmargin=25mm,vmargin=30mm]{geometry}

\makeatletter
\renewenvironment{thebibliography}[1]
      {\list{\@biblabel{\@arabic\c@enumiv}}%
           {\settowidth\labelwidth{\@biblabel{#1}}%
            \leftmargin\labelwidth
            \advance\leftmargin\labelsep
            \@openbib@code
            \usecounter{enumiv}%
            \let\p@enumiv\@empty
            \renewcommand\theenumiv{\@arabic\c@enumiv}}%
      \sloppy
      \clubpenalty4000
      \@clubpenalty \clubpenalty
      \widowpenalty4000%
      \sfcode`\.\@m}
     {\def\@noitemerr
       {\@latex@warning{Empty `thebibliography' environment}}%
      \endlist}

\makeatother

\renewcommand{\baselinestretch}{1.1}

\newcommand{\equadifftitle}[1]{ 
 \begin{center}
  {\Large\bfseries{#1}}
 \end{center}
 \vspace{-1\baselineskip}}

\newcommand{\equadiffauthor}[3]{
	%\index{#4@{\bfseries #2} #1}
	\begin{center}
		{\bfseries #1 #2}\\ {\itshape #3}
	\end{center}
	\vspace{0\baselineskip}}

\begin{document}
\pagestyle{empty}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Here is the place for your abstract (begin) %%%
%%% ------------------------------------------- %%%

\equadifftitle{Here is the title of your abstract}
\equadiffauthor{Firstname}{Surname}{Affiliation}

This is a joint work with Prof XY (University of ..., City, Country). 

Here is the text of your abstract. 
Here is the text of your abstract.
Here is the text of your abstract. 
Here is the text of your abstract. 
Here is the text of your abstract.  

Please do not use your own commands.
Please do not use your own commands.
Please do not use your own commands.
Please do not use your own commands.
Please do not use your own commands.
Please do not use your own commands.

Here is some equation
\begin{equation}
\label{YourSurname:1}
y'=-f(t,y).
\end{equation}
As a label of \eqref{YourSurname:1}, please, use your surname 
followed by ``:'' and a number of the equation.
The same principle use for references, if any, e.g.
\cite{YourSurname:book1} and \cite{YourSurname:article1}.
After compiling the source file, the abstract (incl. the references) should not exceed 1 page of this A4 format.

Please use the abbreviations of journals' names in the list of references in accordance with the rules of Mathematical Reviews,
see \texttt{http://www.ams.org/msnhtml/serials.pdf}.

\vskip\baselineskip

{\small
\begin{thebibliography}{9}

\bibitem{YourSurname:book1} P. Hartman, 
Ordinary differential equations. John Wiley, New York, 1964.

\bibitem{YourSurname:article1} E. Kamke, 
\textit{Zur theorie der systeme gew\"ohnlicher differentialgleichungen, II.} 
Acta Math. \textbf{58} (1932), 57--85.

\end{thebibliography}
}

%%% ------------------------------------------- %%%
%%% Here is the place for your abstract (end)   %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\end{document}
