\begin{table}%t1
\caption{Non-LTE model atoms.}
\label{atoms}
%\centering
\par
\begin{tabular}{ll}
\hline\hline
Ion & Source\\
\hline
\ion{H}{} & Przybilla \& Butler (\cite{PrBu04a})\\
\ion{He}{i} & Husfeld et~al. (\cite{Husfeldetal89}), with updated atomic
data\\
\ion{C}{i/ii} & Przybilla et~al. (\cite{Przybillaetal01b})\\
\ion{N}{i/ii} & Przybilla \& Butler (\cite{PrBu01})\\
\ion{O}{i/ii} & Przybilla et~al. (\cite{Przybillaetal00}) combined with Becker \& \\
& Butler (\cite{BeBu88}), the latter with updated atomic data\\
\ion{Mg}{i/ii} & Przybilla et~al. (\cite{Przybillaetal01a})\\
\ion{S}{ii/iii} & Vrancken et~al. (\cite{Vranckenetal96}), with updated
atomic data\\
\ion{Ti}{ii} & Becker (\cite{Becker98})\\
\ion{Fe}{ii} & Becker (\cite{Becker98})\\
\hline
\end{tabular}
\end{table}