\begin{table}%t1
\caption{\label{table:oxygen}The adopted and derived parameters of the radial oxygen abundance distributions in galaxies.}
%\centering
\par
\begin{tabular}{lrccccl}
 \hline \hline
galaxy       & $R _{\rm 25}$   &  12+log~(O/H)$_0$  &   Gradient      & $\Delta$log~(O/H)  &  Number of  &  References                \\
             & arcmin      &                   & ~dex/R$ _{25}$  &  ~dex             & H~{\sc ii}~regions  &                            \\  \hline
NGC~0224      & 102.07      &    8.76           &    $-$0.52        &   0.09            &   22     & BKC82, BKG99, DK81         \\
NGC~0253      &  14.09      &    8.71           &    $-$0.54        &   0.10            &    9     & WS83                       \\
NGC~0300      &  11.19      &    8.49           &    $-$0.40        &   0.13            &   45     & CPG97, DCL88, dORW83, \\
             &             &                   &                 &                   &          & EP84, PEB79, WS83         \\
NGC~0598      &  37.06      &    8.57           &    $-$0.20        &   0.08            &   41     & BKG99, DTP87, GOS92, KA81,  \\
             &             &                   &                 &                   &          & MRS85, P70, S71, S75, VPD98  \\
NGC~0628      &   5.36      &    8.68           &    $-$0.45        &   0.08            &   37     & BKG99, FGW98, MRS85, vZSH98   \\
NGC~0753      &   1.32      &    8.82           &    $-$0.21        &   0.08            &   12     & HBC96                      \\
NGC~0925      &   5.48      &    8.51           &    $-$0.48        &   0.10            &   20     & vZSH98, ZKH94              \\
NGC~1058      &   1.62      &    8.71           &    $-$0.32        &   0.04            &    6     & FGW98                      \\
NGC~1068      &   3.54      &    8.83           &    $-$0.26        &   0.03            &    9     & OK93, vZSH98               \\
NGC~1232      &   3.71      &    8.73           &    $-$0.58        &   0.09            &   15     & vZSH98                     \\
NGC~1365      &   5.61      &    8.74           &    $-$0.70        &   0.14            &   53     & AEL81, PEB79, RW97         \\
NGC~1637      &   2.04      &    8.67           &     0.02        &   0.11            &   14     & vZSH98                     \\
NGC~2403      &  11.45      &    8.52           &    $-$0.35        &   0.11            &   56     & BKG99, GSP99, GSS97, FTP86, \\
             &             &                   &                 &                   &          & MRS85, S75, vZSH98         \\
NGC~2442      &   3.23      &    8.70           &    $-$0.17        &   0.05            &    8     & R95                        \\
NGC~2541      &   3.30      &    8.23           &     0.14        &   0.14            &   19     & ZKH94                      \\
NGC~2805      &   3.30      &    8.44           &    $-$0.26        &   0.11            &   17     & vZSH98                     \\
NGC~2835      &   3.62      &    8.31           &    $-$0.07        &   0.12            &   17     & R95                        \\
NGC~2841      &   4.06      &    9.12           &    $-$0.78        &   0.01            &    5     & BKG99, OK93                \\
NGC~2903      &   6.29      &    8.94           &    $-$0.71        &   0.09            &   31     & MRS85, vZSH98, ZKH94       \\
NGC~2997      &   5.00      &    8.66           &    $-$0.39        &   0.08            &    6     & EP84, MRS85                \\
NGC~3031      &  13.77      &    8.69           &    $-$0.43        &   0.09            &   36     & BKG99, GS87, OK93, SB84    \\
NGC~3184      &   3.71      &    8.97           &    $-$0.63        &   0.06            &   30     & MRS85, vZSH98, ZKH94       \\
NGC~3198      &   4.26      &    8.69           &    $-$0.64        &   0.07            &   14     & ZKH94                      \\
NGC~3344      &   3.54      &    8.63           &    $-$0.48        &   0.09            &   15     & MRS85, VEP88, ZKH94        \\
NGC~3351      &   3.79      &    8.90           &    $-$0.26        &   0.05            &   19     & BK02, BKG99, MRS85, OK93   \\
NGC~3521      &   5.48      &    8.86           &    $-$0.93        &   0.06            &    9     & ZKH94                      \\
NGC~3621      &   6.74      &    8.55           &    $-$0.44        &   0.12            &   26     & R95, ZKH94                 \\
NGC~4254      &   2.81      &    8.94           &    $-$0.65        &   0.06            &   19     & HPC94, MRS85, SSK91        \\
NGC~4258      &   9.31      &    8.57           &    $-$0.20        &   0.08            &   33     & BKG99, C00, OK93, ZKH94    \\
NGC~4303      &   3.23      &    8.84           &    $-$0.72        &   0.10            &   22     & HPL92, SSK91               \\
NGC~4321      &   3.79      &    8.86           &    $-$0.37        &   0.06            &   10     & MRS85, SSK91               \\
NGC~4395      &   6.59      &    8.27           &    $-$0.02        &   0.08            &   16     & MRS85, vZSH98              \\
NGC~4501      &   3.54      &    8.99           &    $-$0.52        &   0.07            &    5     & SKS96                      \\
NGC~4559      &   5.48      &    8.48           &    $-$0.38        &   0.13            &   20     & ZKH94                      \\
NGC~4571      &   1.86      &    8.90           &    $-$0.20        &   0.04            &    4     & SKS96, SSK91               \\
NGC~4651      &   2.04      &    8.72           &    $-$0.64        &   0.06            &    6     & SKS96                      \\
NGC~4654      &   2.45      &    8.85           &    $-$0.77        &   0.06            &    7     & SKS96                      \\
NGC~4689      &   2.18      &    8.89           &    $-$0.41        &   0.08            &    5     & SKS96, SSK91               \\
NGC~4713      &   1.35      &    8.71           &    $-$0.73        &   0.05            &    4     & SKS96                      \\
NGC~4725      &   5.34      &    9.01           &    $-$0.88        &   0.13            &    8     & ZKH94                      \\
NGC~4736      &   5.61      &    8.60           &    $-$0.26        &   0.05            &   16     & BKG99, MRS85, OK93         \\
NGC~5033      &   5.36      &    9.06           &    $-$1.78        &   0.06            &    5     & ZKH94                      \\
NGC~5055      &   6.29      &    9.01           &    $-$0.83        &   0.07            &    5     & MRS85                      \\
NGC~5068      &   3.88      &    8.32           &    +0.08        &   0.12            &   23     & MRS85, R95                 \\
NGC~5194      &   5.61      &    8.92           &    $-$0.40        &   0.06            &   21     & BKG99, DTV91, MRS85        \\
NGC~5236      &   6.59      &    8.79           &    $-$0.28        &   0.07            &   27     & BK02, DTJ80, WS83          \\
NGC~5457      &  14.42      &    8.80           &    $-$0.88        &   0.09            &   65     & GSP99, KG96, KR94, MRS85, RPT82,  \\
             &             &                   &                 &                   &          & S71, S75, SS78, TPF89, vZSH98        \\
NGC~6384      &   3.38      &    8.90           &    $-$0.62        &   0.05            &   16     & BK02, BKG99, OK93          \\
NGC~6744      &  10.21      &    9.00           &    $-$0.89        &   0.04            &   16     & R95                        \\
NGC~6946      &   8.30      &    8.70           &    $-$0.41        &   0.06            &    9     & FGW98, MRS85               \\
NGC~7331      &   5.74      &    8.68           &    $-$0.48        &   0.04            &   12     & BKG99, OK93, ZKH94         \\
NGC~7793      &   4.78      &    8.54           &    $-$0.50        &   0.07            &   22     & EP84, MRS85, WS83          \\
IC~0342       &  22.33      &    8.85           &    $-$0.90        &   0.12            &    5     & MRS85                      \\
IC~5201       &   4.26      &    8.27           &    +0.09        &   0.14            &   11     & R95                        \\  \hline
\end{tabular}
\end{table}