\begin{table}%t6
%\centering
\par
   \caption{Comparison of the results obtained applying the aperture photometry at the FUV-GALEX image of M~81
   in different regions observed in CO(1--0).}
   \label{table6}
   \begin{tabular}{lcccc}
   \hline
   \hline
   Reference             &  $I_{\rm CO}$       & $F_{\rm FUV}$& $G_{0}$ & $I_{\rm CO}/F_{\rm FUV}$ \\
                         &                 & 10$^{-14}$&& 10$^{14}$  \\
                         & [K~km~s$^{-1}$]   & [erg cm$^{-2}$ s$^{-1}$ $\AA^{-1}$] && [K~km~s$^{-1}$/(erg cm$^{-2}$ s$^{-1}$ $\AA^{-1}$)]\\
   \hline
   \citet{brouillet3}    & 25.90           & 1.37               &0.51              & 18.88\\
   \citet{knapen}        & 20.26           & 1.48               &0.35              & 13.65 \\
   This paper            & 53.50            & 1.13              &0.31               & 47.18 \\
   \hline
   \end{tabular}
   \end{table}