\begin{table}%t1
\par
\caption{\label{ppn}A brief summary of recent
constraints on the PPN-parameters.} 
\small%\centerline
{
\begin{tabular}{l|c}
\hline\hline
  Mercury Perih. Shift $^2$&$|2\gamma_{0}^{\rm PPN}-\beta_{0}^{\rm PPN}-1|<3{\times}10^{-3}$ \\\hline
   Lunar Laser Rang.$^3$ &  $4\beta_{0}^{\rm PPN}-\gamma_{0}^{\rm PPN}-3~=~-(0.7\pm 1){\times}{10^{-3}}$ \\ 
   Very Long Bas. Int.$^4$ &  $|\gamma_{0}^{\rm PPN}-1|~=~4{\times}10^{-4}$ \\ 
  Cassini spacecraft $^5$&  $\gamma_{0}^{\rm PPN}-1~=~(2.1\pm 2.3){\times}10^{-5}$ \\
  \hline
\end{tabular}}
\smallskip
References: $^2$ \citet{mercury}; $^3$ \citet{lls}; $^4$  \citet{VLBI}; and $^5$   \citet{cassini}.
\end{table}