\begin{table}%t5
\caption{\label{table_disc}Lyman-$\alpha$ to Lyman-$\beta$ integrated intensity ratios obtained by various prominence models.}
%\centering
\par
\begin{tabular}{cc}
\hline\hline\noalign{\smallskip}
Type of models & Lyman-$\alpha$/Lyman-$\beta$  \\
\hline\noalign{\smallskip}
1D models without PCTR $^1$  & 90--400 \\
1D models with PCTR $^2$ &  110--280 \\
1D multi-slab models without A.D. $^3$ & 42--111 \\
1D multi-slab models with A.D. $^4$ & 2.3--18.5 \\
\hline
\end{tabular}
\tablebib {$^1$~\citet{1993AetAS...99..513G}; $^2$~\citet{1999AetA...349..974A};
$^3$~\citet{1989HvaOB..13..347V}; $^4$~\citet{1996ApJ...466..496F}.}
\tablefoot {A.D. means ambipolar \mbox{diffusion}.}
\end{table}