\begin{table}%t1
\caption{\label{surveys}Completeness limits and epochs of the different surveys.}
\small%\centerline
 {
\begin{tabular}{lccc}
\hline\hline
Reference                      & $R$             & $I$           & Epoch range  \\
                               & [mag]         & [mag]       & [yr]         \\
\hline                                                                       
\citet{2002AJ....124..404P}    & 16.5          & $\ldots$     & 2000.4--2001.4 \\
\citet{2000AJ....120..479A}    & 19.0          & 18.5        & 1998.2--1991.4 \\
\citet{2004AJ....127..449M}    & $\ldots$       & 18.0        & 1996.2--2000.1 \\
\citet{Martin_inprep}          & $\ldots$       & 18.0        & 1996.2--2000.1 \\
\citet{2008ApJ...688..377S}    & 19.0          & 18.0        & 2004.4        \\
\hline
\end{tabular}}
\medskip
Note. The surveys used different $R$ and $I$-band photometric systems. \citet{2008ApJ...688..377S} survey used $r$ and $i$ rather than $R$ and $I$. Refer to the corresponding articles for more details on each photometric system.
\end{table}