\begin{table}%t1
\caption{\label{tab:ch4-vel-disp-meas-lowi}Summary of   previous observations of gas velocity dispersion in face-on galaxies.}
%\centering
\par
\begin{tabular}{lcccccccccl}
\hline \hline \noalign{\smallskip}
Galaxies & $i$ & Type & H{\scriptsize I} Velocity & 
\multicolumn{2}{c}{Resolution} &
\multicolumn{3}{c}{H{\scriptsize I} radius} & Dist. & Reference \\
& & & dispersion & spectral &
spatial & & & & & \\
& \dg & & & \kms & kpc & kpc & $R_{25}$ & $\theta_{\rm maj}$ & Mpc & \\
\hline \noalign{\smallskip}
NGC 3938 & $10\pm5$ & ScI & constant\tablefootmark{h} & 8.2\tablefootmark{a} &
$1.2 \times 1.7$ & 13.1 & 1.7
& 7.5 & 10 & \citet{vdks1982c} \\
NGC 628 & $5\pm5$\tablefootmark{e} & ScI & falling\tablefootmark{h} & 8.2\tablefootmark{a} &
 $2.9 \times 2.9$ & 40.7 & 2.8 & 14.0 &
10 & \citet{svdk1984} \\
NGC 1058 & $8\pm2$\tablefootmark{f} & Sc{\sc II-III} & constant\tablefootmark{h} &
8.2\tablefootmark{a} & $2.2 \times 2.2$\tablefootmark{c} & 18.9 & 4.3 & 8.7 & 10\tablefootmark{c} &
\citet{vdks1984} \\
NGC 1058 & $8\pm2$\tablefootmark{f} & Sc{\sc II-III} & falling\tablefootmark{h} &
2.58\tablefootmark{a} & $2.1 \times 2.0$\tablefootmark{d} & 14.1 & 3.2 & 6.7 & 10\tablefootmark{d} &
\citet{dhh1990} \\
NGC 6946 & 34 & Scd/Sc{\sc I} & falling\tablefootmark{h} & 8.25\tablefootmark{a} & $0.7 \times 0.8$ & 17.2 & 2.0 & 21.2 & $5.9$\tablefootmark{b} & \citet{bv1992} \\
NGC 5474\tablefootmark{g} & $21^{+4}_{-6}$ & ScdIV & falling\tablefootmark{h} & 5.2\tablefootmark{a} & $1.2 \times 1.1$ & 10.5 & 4.6 & 8.6 & 7 & \citet{rdh1994} \\
NGC 1058 & $8\pm2$\tablefootmark{f} & Sc{\sc II-III} & falling\tablefootmark{h} & 2.58\tablefootmark{a} & $1.5 \times 1.5$ & 21.8 & 5.0 & 15.0 & 10 & \citet{pr2006} \\
\hline
\end{tabular}
\tablefoot {\tablefoottext{a}{Hanning smoothed.} \\
\tablefoottext{b}{Distance shown is mean distance calculated from brightest stars in NGC~6946 group.} \\
\tablefoottext{c}{To facilitate comparison with the other observations for NGC~1058, we have used the adopted distance of $10$~Mpc used by \citet{pr2006}, rather than the \citet{vdks1984} preferred value of~$9$~Mpc.} \\
\tablefoottext{d}{To facilitate comparison with the other observations for NGC~1058, we have used the adopted distance of~$10$~Mpc used by \citet{pr2006}, rather than the \citet{dhh1990} preferred value of $10.2{-}14.5$~Mpc.} \\
\tablefoottext{e}{Warps from ${\approx}5^{\circ}$ within the optical disk to $i\approx0^{\circ}$, then back to $i\approx10^{\circ}$ at the H{\scriptsize I}~edge \citep{svdk1984}.} \\
\tablefoottext{f}{Warps from ${\approx}8$~$\pm$ $2^{\circ}$ within the optical disk to exactly face-on at the H{\scriptsize I}~edge \citep{vdks1984}.} \\
\tablefoottext{g}{Classified as peculiar, and known to be interacting with its much larger neighbour~M101 which is only $90$~kpc distance assuming a distance of $7$~Mpc \citep{rdh1994}.} \\
\tablefoottext{h}{Direct measurement of the velocity dispersion of the broadening of the vertical velocity dispersion from a near face-on disk. Measurements corrected for instrumental broadening and
inclination, but not beam-smearing.}}
\vspace*{2.5mm}
\end{table}