\begin{overpic}[width=0.49\textwidth]{chd-4}
\put(1,74){\colorbox{white}{(\sublabel{chd-4}) \href{http://dream.misasa.okayama-u.ac.jp/?q=20120705150605-805-601}{chd-4}}}
%%(\subref{chd-4}) \href{chd-4}
\color{red}
\end{overpic}
<?xml version="1.0" encoding="UTF-8"?>
<acquisitions>
</acquisitions>