\begin{table}%t6
\caption{Ionised boundary layer pressures and internal pressures and densities of clouds observed in molecular line wavelengths. A dash indicates non-detection in the NVSS.}
\label{tbl:Pint}
%\centerline
{
\begin{tabular}{ccccc}
\hline  \hline
SFO object & IBL pressure & &Internal pressure & Internal molecular density \\
 & (10$^{5}$ cm$^{-3}$ K/$k_{\rm B}$) & & (10$^{5}$ cm$^{-3}$ K/$k_{\rm B}$) &  $(10^3~\rm cm^{-3})$\\ \hline
4$^{a}$	 & 197.5 &$\gg$& 8.2   & 50.0   \\
5$^{b}$	 & 114.4 &    & 32.3  & 11.0  \\	    
11$^{c}$ & 82.0  &    & 25.0  & 2.5    \\
13$^{d}$ & 63.9  &$\gg$& 16.3  & 2.0    \\
16$^{d}$ &  --	 &    & 0.3   & 2.0    \\
18$^{d}$ &  --	 &    & 7.8   & 16.6   \\
20$^{e}$ &  --	 &    & 6.9   & 20.0   \\
25$^{d}$ & 66.4  &    & 12.5  & 7.4    \\
37$^{f}$ & 112.3 &$\gg$& 1.5   & 3.0    \\\hline	    
\end{tabular}}
\medskip
$^{a}$ \citet{Jansen94}; $^{b} $\citet{Lefloch97}; $^{c}$ \citet{searching}; $^{d}$ \citet{Devries}; $^{e}$ \citet{Cernicharo1992}; $^{f}$ \citet{Duvert1990}.	
\end{table}