\begin{table}%t2
\par
\caption{\label{tab:sources}Source parameters.}
\begin{tabular}{lccccc}
\hline
\hline
\noalign{\smallskip}
Name & RA  & DEC & $V_{\rm LSR}$ & $N_{\rm H}$\tablefootmark{a} & $N({\rm H})$\\
     & J2000 & J2000 & \kms  &  10$^{22}$ cm$^{-2}$ & 10$^{22}$ cm$^{-2}$\\
\hline
W31C\tablefootmark{b} & 18:10:28.7  &  $-19$:55:50.0 & $-2$  & $2.7$ & $1.2$ \\
W49N & 19:10:13.2& 09:06:12 & 11 & $4.1$& $1.4 $\\
W51\tablefootmark{c} &19:23:43.9  &  14:30:30.5 & 57& $2.5$  & $0.8$  \\
\hline
\end{tabular}
\tablefoot{
\tablefoottext{a}{Total hydrogen: $N_{\rm H}=2N({\rm H}_2)+N({\rm H}).$, 
see text.}
\tablefoottext{b}{Also known as G10.6$-$0.64.}
\tablefoottext{c}{W51-E4.}}
\end{table}