\documentclass[a4paper]{article}
\usepackage{psfrag,pdfrack}
\usepackage{graphicx}
\begin{document}
Some text.
\begin{figure}
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 \psfrag{CC}{$\mathcal{C}_C$}
 \psfrag{AB}{$\overrightarrow{AB}$}
 \psfrag{AC}{$\overrightarrow{AC}$}
 \psfrag{BC}{$\overrightarrow{BC}$}
 \pdfrackincludegraphics[width=.6\linewidth]{OneFigure}
\end{figure}
\begin{figure}
 \psfrag{IN}{$\displaystyle \int_0^{g(t)}e^{f(x)}\mathrm{d}x$}
 \psfrag{OUT}{$\displaystyle \int_0^{t}\Theta(x)\mathrm{d}x$}
 \psfrag{BASE}{$t$}
 \pdfrackincludegraphics[width=.8\linewidth]{OtherFigure}
\end{figure}


\begin{figure}[htbp]
 \begin{center}
   \psfrag{CA}{$\mathcal{C}_A$}
   \psfrag{CB}{$\mathcal{C}_B$}
   \psfrag{CC}{$\mathcal{C}_C$}
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   \psfrag{BC}{$\overrightarrow{BC}$}
   \pdfrackincludegraphics[width=.6\linewidth]{OneFigureAgain}
   \psfrag{IN}{$\displaystyle \int_0^{g(t)}e^{f(x)}\mathrm{d}x$}
   \psfrag{OUT}{$\displaystyle \int_0^{t}\Theta(x)\mathrm{d}x$}
   \psfrag{BASE}{$t$}
   \pdfrackincludegraphics[width=.8\linewidth]{OtherFigureAgain}
 \end{center}
\end{figure}

\end{document}