\documentclass[a4paper]{article}
\usepackage{psfrag,pdfrack}
\begin{document}
Some text.
\begin{figure}[htbp]
  \begin{center}
    \psfrag{CA}{$\mathcal{C}_A$}
    \psfrag{CB}{$\mathcal{C}_B$}
    \psfrag{CC}{$\mathcal{C}_C$}
    \psfrag{AB}{$\overrightarrow{AB}$}
    \psfrag{AC}{$\overrightarrow{AC}$}
    \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}