\begin{table}%t3
\caption{\label{tab:results}Results.}
%\centering
\par
\begin{tabular}{lllll}
\hline
\hline
Source & $T_{\rm ex}^{54}$\tablefootmark{a} & $N_{\rm HNCO}$\tablefootmark{b} & $N_{\rm HNCO}$\tablefootmark{c} & $X$(HNCO)\tablefootmark{d} \\
       &  K  & 10$^{13}$ \cmmd & 10$^{13}$ \cmmd & 10$^{-9}$ \\
\hline
mm     & 8--11          & 0.2--1.3    & 0.2--1.3  & 0.3--1.2 \\
B1     & 11--19         & 0.6--2.5    & 0.6--2.5  & 4.3--17.9 \\
B2     & 9--16          & 1.3--5.0    & 1.3--5.0  & 25--96   \\
\hline
\end{tabular}
\tablefoot{\tablefoottext{a}{Excitation temperatures derived from the populations  in the 
$5_{0,5}$ and $4_{0,4}$ levels.}
\tablefoottext{b}{HNCO column density assuming LTE, optically thin lines and 
extrapolating using $T_{\rm ex}^{54}$.}
\tablefoottext{c}{HNCO column density computed  using {\sc radex}.}
\tablefoottext{d}{HNCO abundance with respect to H$_2$  \citep[using the 
H$_2$ column densities given by][]{Bachiller97}.}}
\end{table}