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\begin{document}
\tablenum{4}
\begin{deluxetable}{llc}
\tablewidth{25pc}
\tablecaption{Metallicity ([Fe/H]) of NGC 4833 from RGB photometric parameters}
\tablehead{\colhead{Calibration} & \colhead{Reference} & \colhead{[Fe/H]}}
\startdata
$4.30(B-V)_{0,g}-5.00$ & Zinn \& West 1984 &  $-2.16$\\
$3.84(B-V)_{0,g}-4.63$ & Gratton 1987      &  $-2.10$\\
$4.68(B-V)_{0,g}-5.19$ & Costar \& Smith 1988 & $ -2.10$\\
$2.85(B-V)_{0,g}-3.76$ & Gratton \& Ortolani 1989 & $-1.88$\\
\noalign{\medskip}
\hline
\noalign{\medskip}
$-0.924\Delta{}V_{1.4}+0.913$& Zinn \& West 1984 & $-1.96$\\
$-1.01\Delta{}V_{1.4}+1.30$&Costar \& Smith 1988 & $-1.84$\\
$-0.65\Delta{}V_{1.4}+0.28$&Gratton \& Ortolani 1989 & $-1.74$\\
\noalign{\medskip}
\hline
\noalign{\medskip}
&  Mean:& $-1.97$
\enddata
\end{deluxetable}
\end{document}