\begin{table}%t5
\caption{\label{table5}Optical decay indexes and comparison with the X-ray band
decay indexes.}
\small%\centerline
{
\begin{tabular}{cccc}
  \hline\hline
  GRB~& $\rm \delta_{\rm O}$ & $\rm \delta_{\rm X} - \delta_{\rm O}$ & Reference \\
  \hline
\object{GRB~970228} & $\rm 1.21\pm0.02$ & $\rm 0.1 \pm 0.2$   & 1 \\
\object{GRB~970508} & $\rm 0.15\pm0.02$ & $\rm 0.65 \pm 0.2$  & 2 \\
\object{GRB~971214} & $\rm 1.20\pm0.02$ & $\rm -0.2\pm 0.3$   & 3 \\
\object{GRB~980329} & $\rm 1.3\pm0.2$   & $\rm 0.1 \pm 0.6$   & 4 \\
\object{GRB~980613} & $\rm 0.8\pm0.5$   & $\rm 0.7^{+1.1}_{-2.0}$ & 5 \\
\object{GRB~980703} & $\rm 1.2\pm0.4$   & $\rm -0.1\pm 0.5$   & 6 \\
\object{GRB~990123} & $\rm 1.1\pm0.4$   & $\rm 0.3 \pm 0.4$   & 7 \\
\object{GRB~990510} & $\rm 0.8\pm0.2$   & $\rm 0.6 \pm 0.3$   & 8 \\
\object{GRB~010222} & $\rm 1.32\pm0.03$ & $\rm 0.03 \pm 0.07$ & 9 \\
\object{GRB~011121} & $\rm 1.6\pm0.6$   & $\rm -0.3\pm 0.6$   & 10\\
\object{GRB~011211} & $\rm 0.95\pm0.2$  & $\rm 1.2 \pm 0.4$   & 11\\
\object{GRB~020322} & $\rm 0.5\pm0.3$   & $\rm 0.3 \pm 0.5$   & 12, 13\\
  \hline
\end{tabular}}
\smallskip
References: 1: \citet{mas98}, 2: \citet[][ the index shown is
relative to the BeppoSAX observation interval]{gal98}, 3:
\citet{die98}, 4: \citet{rei99}, 5: \citet{hjo02}, 6:~\citet{blo99},
7: \citet{kul99}, 8: \citet{har99}, 9:~\citet{mas01}, 10:
\citet{pri02}, 11: \citet{jac03}, 12: \citet{blo02}, 13:
\citet{gre02}.
\end{table}