\begin{table}%t4
\caption{\label{tab2}Frequencies, amplitudes and confidence levels for the three
datasets analysed in this paper. The error bars on the frequencies are~$\pm$0.11~c/d, $\pm$0.15~c/d and~$\pm$0.25~c/d for the datasets 2003~$V$, 2003~$B$ and 2002~$B$~datasets, respectively. Note that for the 2003~$B$
and~2002~$B$~datasets the frequencies are not listed by decreasing
amplitude, but by correspondence with the 2003~$V$~dataset frequencies
(see text).}
%\centering
\par
\begin{tabular}{cccc|ccc|ccc}
\hline\hline
\multicolumn{4}{c}{2003 $V$ dataset} & \multicolumn{3}{c}{2003 $B$ dataset} & \multicolumn{3}{c}{2002 $B$ dataset}\\
\hline
%\noalign{\smallskip}
  & Frequency   &   Amplitude  & confidence  & Frequency   &   Amplitude  & confidence   & Frequency   &   Amplitude  & confidence \\
  & (c/d)       &    (mmag)    & (\%)        & (c/d)       &    (mmag)    & (\%)         & (c/d)       &    (mmag)    & (\%) \\
%\noalign{\smallskip}
\hline
%\noalign{\smallskip}
$f_1$  & 22.89     & 1.9 & 99.9  & 22.89      & 3.1 & 99.9 &  22.88    & 3.3 & 99.9  \\
$f_2$  & 34.60     & 1.5 & 99.9  & 34.82      & 2.1 & 99.9 &  34.64    & 3.3 & 99.9  \\
$f_3$  & 30.45     & 1.8 & 99.9  & 30.45      & 1.8 & 99.9 &  30.48    & 3.2 & 99.9  \\
$f_4$  & 48.23     & 1.6 & 99.9  & 48.45      & 2.0 & 99.9 &  48.23    & 1.9 & 99.9  \\
$f_5$  & 28.79     & 1.5 & 99.9  &            &     &      &  27.73    & 1.9 & 99.9  \\
$f_6$  & 23.99     & 1.3 & 99.9  &            &     &      &           &     &       \\
$f_7$  &  9.30     & 1.3 & 99.9  &            &     &      &           &     &       \\
$f_8$  & 41.11     & 1.2 & 99.9  & 42.08      & 1.9 & 99.0 &  42.27    & 2.3 & 99.9  \\
$f_9$  & 52.00     & 1.1 & 99.9  &            &     &      &           &     &       \\
\hline
\end{tabular}
\end{table}