\documentclass[12pt]{article}
\usepackage{amsthm,amsmath,amssymb,ifthen}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\setlength{\oddsidemargin}{0.7cm}
\setlength{\evensidemargin}{0.7cm}
\setlength{\textwidth}{15.3cm}
\setlength{\textheight}{23.7cm}
\setlength{\topmargin}{-1.0cm}
\pagestyle{empty}
\parindent=6mm

\def\N{\mathbb{N}}
\def\R{\mathbb{R}}
\def\Q{\mathbb{Q}}
\def\Z{\mathbb{Z}}
\def\C{\mathbb{C}}

\newcommand{\header}{\begin{center}
{\LARGE\sc $55$\textsuperscript{\rm{th}}\, International Symposium \\[2mm] on Functional Equations}\\[2mm]
{\large\bf Hongwa Hotel, Chengdu, China, June 11--18, 2017}
\end{center}\vspace{-3mm}\hrule\vspace{3mm}}

\newcommand{\abst}[6]{%\newpage
\setcounter{equation}{0}
\header\vspace{1cm}\begin{center}
{\LARGE\bf #4}\\[4mm]{\Large\sc #2 #1}\\[1mm]{\large #3}\\[2mm]
\ifthenelse{\equal{#5}{}}{}{{\large (joint work with \sc #5)}}
\end{center}\vspace{7mm}\noindent #6}

\newenvironment{Refes}{\bigskip \noindent \small {\sc References}
    \begin{list}{--}{\leftmargin=\parindent}\itemsep=-2pt}{\end{list} \normalsize}
\newenvironment{Refe}{\bigskip \noindent \small {\sc Reference}
    \begin{list}{--}{\leftmargin=\parindent}\itemsep=-2pt}{\end{list} \normalsize}


\begin{document}

\abst{Surname}{Given name(s)}{University}
{Title}{Co-author(s)}{Text of the abstract of at most 10 lines.

\begin{Refes}
\item [1.] This is the first reference
\item [2.] This is the second reference
\end{Refes}
}

\end{document}
