\begin{table}%t4
\caption{Reduced $\chi^2$ values for the best fit spectra of~Mkn~421 with a power 
law with exponential cutoff and a log-parabola for the~\mbox{1999-2000} observations.}
\label{tab4}
%\centering
\par
\begin{tabular}{lccc}
\hline \hline
Date & PL+EC & Log $P$ & d.o.f. \\
\hline
1999-05    &  ~4.16 & 1.11 & 141  \\
 ~~~~~I    &  ~1.57 & 1.11 & 111  \\ 
 ~~~~II    &  ~3.22 & 1.14 & 111  \\ 
 ~~~III    &  ~2.51 & 1.06 & 111  \\ 
 ~~~IV     &  ~1.77 & 1.04 & 111  \\ 
%           &       &      &      \\
%           &       &      &      \\
2000-04    &  13.11 & 1.06 & 152  \\
 ~~~~~H    &  ~8.13 & 1.01 & 152  \\
 ~~~~~F    &  ~8.21 & 1.06 & 152  \\
%           &       &      &      \\  
2000-05    &  ~7.89 & 1.34 & 149  \\
 ~~~~~I    &  ~5.82 & 1.37 & 149  \\ 
 ~~~~II    &  ~2.77 & 1.03 & 136  \\ 
 ~~~III    &  ~2.87 & 1.26 & 136  \\
 ~~~IV     &  ~2.14 & 0.87 & 136  \\
 ~~~~V     &  ~1.67 & 1.00 & 121  \\
\hline
\end{tabular}
\end{table}