\begin{table}
\caption{Atomic data references for ORL analysis.\label{reforl}}
%\centerline
{
\begin{tabular}{lll}
\hline\hline
{Ion} & {Effective recomb. coeffs.} &{Comment} \\
\hline
H~{\sc i}  & \citet{storey1995}      & Case B    \\
He~{\sc i} & \citet{benjamin}    & Case B; singlets \\
            & \citet{brocklehurst1972}& Case A; triplets \\
He~{\sc ii}& \citet{storey1995}      & Case B    \\
C~{\sc ii} & \citet{davey2000}       & Case B    \\
C~{\sc iii}& \citet{pequignot1991}   & Case A    \\
            & \citet{nussbaumer1984}  & Dielectronic recom.\\
C~{\sc iv} & \citet{pequignot1991}   & Case A    \\
N~{\sc ii} & \citet{kisielius2002}   & Case B; triplets \\
            & \citet{escalante1990}   & Case A; singlets \\
N~{\sc iii}& \citet{pequignot1991}   & Case A    \\
            & \citet{nussbaumer1984}  & Dielectronic recom.\\
N~{\sc iv} & \citet{pequignot1991}   & Case A    \\
            & \citet{nussbaumer1984}  & Dielectronic recom.\\
N~{\sc v}  & \citet{pequignot1991}   & Case A    \\
O~{\sc ii} & \citet{storey94}        & Case B; quartets \\
            & \citet{liu1995}         & Case A; doublets \\
O~{\sc iii}& \citet{pequignot1991}   & Case A    \\
O~{\sc iv} & \citet{pequignot1991}   & Case A    \\
            & \citet{nussbaumer1984}  & Dielectronic recom.\\
O~{\sc v}  & \citet{pequignot1991}   & Case A    \\
Ne~{\sc ii}& \citet{kisielius1998}   & Case B; doublets \\
            & Storey (unpublished)      & Case A; quartets \\
Mg~{\sc ii} & \citet{davey2000}$^a$ & Case B    \\
\hline\end{tabular}}
\medskip
$^{a}$ Given the similarity between the atomic structure of \ion{Mg}{ii} and \ion{C}{ii},
we have assumed that the \ion{Mg}{ii} 3d--4f $\lambda$4481 line has an
effective recombination coefficient equal to that of the \ion{C}{ii} 3d--4f
$\lambda$4267 line.
\end{table}