\begin{table}%t2
\caption{\label{Cal-mean-sigma}Metallicity calibrations evaluated in Sect.~\ref{Sect:met}.}
%\centering
\par
\begin{tabular}{l l l l l r  r  l}
\hline \hline
\noalign{\smallskip}
Reference    & \multicolumn{2}{c}{$(b-y)_0$} &  \multicolumn{2}{c}{[Fe/H]} & \multirow{2}{*}{$\langle$[Fe/H]$-$[M/H]$\rangle$ $\pm$ $\sigma$} & \multirow{2}{*}{Comment} \\
& min & max &  min & max & &  \\
\hline
Olsen (1984)       & 0.29 & 1.00      & --2.60 & 0.39  &  0.11  $\pm$  0.34 & Their Eq.~(15)\\
                         & 0.514 & 1.000 & --2.60 & 0.39 &   0.04 $\pm$ 0.39 & Their Eq.~(15)\\
                        & 0.514 & 1.000 & --0.25 & 0.60 &   0.02 $\pm$ 0.17 & Their Eq.~(16) \\
Schuster \& Nissen (1989b)  & 0.22  & 0.38  & --3.5  & 0.2  &  \multirow{2}{*}{0.06 $\pm$ 0.16} & F-type dwarfs \\
                                 & 0.37  & 0.59  & --2.6  & 0.4  &   & G-type dwarfs \\
Haywood (2002)            &  0.22  & 0.59  & --2.0  & 0.5  &   0.00 $\pm$ 0.18 & \\
Martell \& Laughlin (2002) & 0.288 & 0.591 & --2.0  & 0.5  &   0.05 $\pm$ 0.13 &\\
Martell \& Smith (2004)    & 0.288 & 0.591 & --2.0  & 0.5  &   0.06 $\pm$ 0.21 &\\
Nordstr\"{o}m et~al. (2004)& 0.18  & 0.38  & --2.0  & 0.8  & --0.17 $\pm$ 0.52 &\\
                                      & 0.44  & 0.59  & --2.0  & 0.8  &   0.13 $\pm$ 0.08 & \\
Ram\'{i}rez \& Mel\'{e}ndez (2005a) & 0.19  & 0.35   & --3.5 & 0.4  & \multirow{2}{*}{0.04 $\pm$ 0.14} & F-type dwarfs \\
                                      & 0.35  & 0.80   & --2.5 & 0.4  &  & G-type dwarfs \\
Holmberg et~al. (2007)     & 0.24  & 0.63  & --1.00 & 0.37 &   0.08 $\pm$ 0.16 &\\
\hline
\"{O}nehag et~al. (2008)       & 0.22 & 0.59  &   --3.5 & 0.4  & 0.33 $\pm$ 0.30 &\\
\hline
\end{tabular}
\tablefoot {Column 1 lists the reference for the calibration.  In Cols.~2 to~5 we quote the ranges, for for $(b-y)_0$ and [Fe/H], within which the calibrations is valid.  Column~6 gives the mean difference between [Fe/H] and [M/H] and the associated $\sigma$. Column~7 provides additional comments.}
\end{table}