\begin{table}%T3
\small
\caption{Amplitudes, $\Delta V_0$ and $\Delta V_1$, of 
$f_0=25.5769$~cd$^{-1}$ and $f_1$, respectively, determined from 
different data sets by Fourier analysis.}\label{t3}
%\centerline
{
\small
\begin{tabular}{crrrcc}  \hline\hline
Year & $\Delta V_0$~~ & $f_1$~~ & $\Delta V_1$~~ & Source & Notes \\
~ & (mmag) & (cd$^{-1}$) & (mmag) & ~ & ~ \\ \hline
1993  &   140.4 &     --      &   --   &        1   &      ~\\
~     &     2.6 &     ~      &   ~   &        ~   &      ~\\
1994  &   160.3 &     --      &   --   &        1   &      ~\\
~     &     2.1 &     ~      &   ~   &        ~   &      ~\\
1995  &   146.5 &     32.567 &   9.0 &        1   &      ~\\
~     &     1.3 &     ~      &   1.3 &        ~   &      ~\\
1996  &   141.6 &     --      &   --   &        1   &      ~\\
~     &     2.0 &     ~      &   ~   &        ~   &      ~\\
1996  &   142.8 &     32.689 &  13.2 &        2   &      a\\
~     &     4.1 &     ~      &   4.1 &        ~   &      ~\\
1996  &   159.8 &     32.706 &  13.7 &        2   &      b\\
~     &     4.4 &     ~      &   4.4 &        ~   &      ~\\
1996  &   146.8 &     31.593 &  11.5 &        3   &      ~\\
~     &     1.1 &     ~      &   1.1 &        ~   &      ~\\
1999  &   145.7 &     31.676 &   7.0 &        4   &      c\\
~     &     0.5 &     ~      &   0.5 &        ~   &      ~\\
2000  &   149.1 &     31.683 &  10.0 &        5   &      ~\\
~     &     1.3 &     ~      &   1.3 &        ~   &      ~\\
2001  &   151.9 &     --      &  --    &        5   &      ~\\
~     &     2.6 &     ~      &  ~    &        ~   &      ~\\
2001  &   138.1 &     31.629 &  17.0 &        6   &      ~\\
~     &     1.3 &     ~      &   1.3 &        ~   &      ~\\
2003  &   153.8 &     32.711 &  14.4 &        2   &      d\\
~     &     1.0 &     ~      &   1.0 &        ~   &      ~\\
2003  &   146.9 &     30.618 &   9.6 &        7   &      e\\
~     &     1.0 &     ~      &   1.0 &        ~   &      ~\\
2004  &   137.3 &     --      &   --   &        8   &      f\\
~     &     5.4 &     ~      &   ~   &        ~   &      ~\\
2004  &   144.8 &     --      &   --   &        9   &      ~\\
~     &     2.4 &     ~      &   ~   &        ~   &      ~\\
2005  &   149.3 &     --      &   --   &        9   &      ~\\
~     &     5.8 &     ~      &   ~   &        ~   &      ~\\
\hline
\end{tabular}}
\medskip
Sources: 1)~Hintz et~al. (\cite{Hintz97}), 
2)~present work, Ch\^ateau-Renard Observatory, 3)~Zhou et~al. (\cite{Zhou99}), 
4)~Zhou et~al. (\cite{Zhou01}), 5)~Kim et~al. (\cite{Kim03}), 6)~Wolf et~al. (\cite{Wolf02}), 7)~present 
work, Xinglong Station, 8)~present work, McDonald Observatory, 9)~present 
work, Mo~i Rana Observatory. 
Notes: 
a)~observations in Johnson $B$ filter, $\Delta V$ is determined from 
$\Delta V=0.80\Delta B$ (see text), 
b)~observations in $R$ filter, $\Delta V$ is determined from 
$\Delta V=1.36\Delta R$ (see text), 
c)~another peak is detected at 32.5456~cd$^{-1}$, with 
$\Delta V=5.6(\pm0.5)$~mmag and ${\it S/N}=5.6$, 
d)~this data set include the data from October 2003 to February 2004. 
$\Delta V$ is calculated from $\Delta V=1.36\Delta R$ (see text), 
e)~$f_1=30.618$~cd$^{-1}$ can be an 1~cd$^{-1}$ alias of 31.6~cd$^{-1}$, 
although the corresponding amplitude {\it S/N} ratio is rather low (${\it S/N}=3.9$), 
f)~observations in filter $S$ (Schott BG40), $\Delta V$ is determined from 
$\Delta V=0.88\Delta S$ (see text).
\end{table}