\begin{table}%t1
\caption{Observed sample of Cepheids sorted by increasing period.
\label{Tab_Cepheids_Parameters}}
\small%\centerline
{
\begin{tabular}{lcccccc}
\hline \hline \noalign{\smallskip}
Name     &  HD     &  $P^a$          & $T_0^a$                     & Nb.               & Nb. of            & ${m_{\rm V}}^b$ \\
         &         &  [days]         & [days]                                &  of spectra       & cycles                                             \\
\hline
R TrA       & 135592  &   $3.38925$     &  $2~451~649.96$         &       14               &               15 &      6.66\\
S Cru       & 112044  &   $4.68976$     &  $2~451~645.64$         &       12               &               3  &  6.60   \\
Y Sgr       & 168608  &   $5.77338$     &  $2~451~650.92$         &       17               &               10 & 5.74  \\
$\beta$ Dor & 37350   &   $9.84262$     &  $2~451~643.54$         &       49               &            3     & 3.75   \\
$\zeta$ Gem & 52973   &   $10.14960$    &  $2~451~641.78$         & 50                     & 3                & 3.90   \\
Y Oph       & 162714  &   $17.12520$    &  $2~451~653.32$         & 7                      & 4                & 6.17  \\
RZ Vel      & 73502   &   $20.40020$    &  $2~451~633.58$         & 10                     &  3               & 7.08  \\
$\ell$~Car  & 84810  &   $35.551341$    &  $2~452~290.4158$          & 118                    & 2                & 3.74  \\
RS~Pup      & 68860   &   $41.51500$    &  $2~451~644.22$         & 15                     & 3                & 7.03 \\
\hline  
\end{tabular}}
\smallskip
 $^{{a}}$  For $\ell$~Car, the reference Julian date ($T_0$) and the pulsation
period ($P$) used to compute the phase are from Szabados
(\cite{Szabados89}). For others stars we used ephemeris from Berdnikov
et~al. (\cite{Berdnikov01}).\\
$^{{b}}$ The visible magnitude (${m_{\rm V}}$) is
from Berdnikov et~al. (\cite{Berdnikov00}).
\end{table}