\begin{table}%T1
   \caption{Number of TPs with TDU, total
    TDU mass, and C, N, and F yields (all in \Msun) for different AGB
    models of 2\Msun~at [Fe/H$] = -2.3$. \label{tab:uncertain_yields} }
    \small%\centerline
{
\begin{tabular}{llccccc} 
\hline \hline 
& Model & TPs & $M_{\rm TDU}$ & C & N & F \\ 
\hline 
1&Karakas$^a$ & 25 & 0.22 & 3.7E-02 & 7.2E-05 & 1.1E-05 \\ 
2&pocket$^b$ & " & " & " & " & 1.7E-05 \\ 
3&$^{18}$F($\alpha$,~p) UL$^b$ & " & " & " & " & 2.8E-05 \\ 
4&pocket + UL$^b$ & " & " & " & " & 3.3E-05 \\ 
 5&Cristallo$^c$ & 14 & 0.09 & 1.7E-02 & 3.4E-05 & 2.4E-06 \\ 
6&Cristallo$^d$ & 49 & 0.19 & 3.1E-2 & 1.2E-4 & 1.1E-05 \\ 
\hline 
\end{tabular}} 
\smallskip
$^a$ \citet{lugaro04} and \citet{karakas07b};
$^b$\citet{karakas08};
$^c$\citet{cristallo07}; $^d$\citet{cristalloThesis}.
 \end{table}