\begin{table}%t6
\caption{\label{table:06}Coefficients of the 
         best-fit polynomials for the observed relations between 
         the emission-line flux ratios and the oxygen abundance,
         where $\log~R = b_0 + b_1 y + b_2 y^2 + b_3 y^3$
         [$y \equiv 12+\log($O/H)].}
\small%\centering
\par
\begin{tabular}{l c c c c }
\hline\hline
Flux ratio (log $R$) & 
$b_0$ &
$b_1$ &
$b_2$ &
$b_3$ \\
\hline 
log $R_{23}$ &
   +1.2299E+0 & --4.1926E+0 &  +1.0246E+0 & --6.3169E--2 \\
log [$F$([N{\sc ii}]$\lambda6584$)/$F$(H$\alpha$)] &
   +9.6641E+1 & --3.9941E+1 &  +5.2227E+0 & --2.2040E--1 \\ 
log [$F$([O{\sc iii}]$\lambda$5007)/$F$([N{\sc ii}]$\lambda$6584)] &
  --2.3218E+2 &  +8.4423E+1 & --9.9330E+0 &  +3.7941E--1 \\
log [$F$([N{\sc ii}]$\lambda$6584)/$F$([O{\sc ii}]$\lambda$3727)] &
  --1.2894E+2 &  +4.8818E+1 & --6.2759E+0 &  +2.7101E--1 \\
log [$F$([N{\sc ii}]$\lambda$6584)/$F$([S{\sc ii}]$\lambda$6720)] &
  --8.0632E+1 &  +3.1323E+1 & --4.1010E+0 &  +1.7963E--1 \\
log [$F$([O{\sc iii}]$\lambda$5007)/$F$([O{\sc ii}]$\lambda$3727)] &
  --1.4089E+0 &  +1.3745E+0 & --1.4359E--1& --- \\
\hline
\end{tabular}
\end{table}