引用章节
\section{Chapter1}
\label{sec:chapter1} % define label
\section{Chaprter2}
Chapter1 can be find in Section \ref{sec:chapter1}.
子图
\begin{figure}[!t]
\centering
\subfloat[sublabel_1]{
\includegraphics[width=3.5in]{fig_1.pdf}%
\label{fig:fig_1}
}
\hfil
\subfloat[sublabel_2]{
\includegraphics[width=3.5in]{fig_2.pdf}%
\label{fig:fig_2}
}
\caption{Description of the figures.}
\label{fig:fig_1_2}
\end{figure}