\begin{table}%t5
\caption{Equivalent width measurements (in~\AA) corresponding to the 9 DBs analysed
in our sample of post-AGB stars.}
\label{tb:intensidades}
\small%\centerline
{
\begin{tabular}{l r r r r r r r r r}\hline\hline\noalign{\smallskip}
\multicolumn{1}{c}{}    & \multicolumn{9}{c}{$EW$ (\AA)}\\
IRAS name     &   5780~~~~        &   5797~~~~~         &   5850~~~~~            &   6196~~~~~            &   6284~~~~            &   6379~~~~            &   6614~~~~            &   6993~~~~            &   7224~~~~            \\
\hline
 01005$+$7910   &   0.08    $\pm$   0.04    &   0.021   $\pm$   0.009   &   $\le$0.01    &   0.029   $\pm$   0.009   &   0.18    $\pm$   0.09    &   0.025   $\pm$   0.009   &   0.045   $\pm$   0.009   &   0.034   $\pm$   0.009   &   $\le$0.01    \\
 02229$+$6208   &   0.18    $\pm$   0.06    &   0.043   $\pm$   0.009   &   ?           &   0.076   $\pm$   0.009   &   0.87    $\pm$   0.09    &   0.053   $\pm$   0.009   &   ?           &   0.012   $\pm$   0.009   &   ?           \\
 04296$+$3429   &   0.20    $\pm$   0.06    &   $\le$0.03    &   --         &   ?           &   0.66    $\pm$   0.08    &   0.058   $\pm$   0.009   &   0.16    $\pm$   0.01    &   --         &   ?           \\
 05113$+$1347   &   0.27    $\pm$   0.06    &   $\le$0.04    &   ?           &   ?           &   ?           &   ?           &   0.045   $\pm$   0.009   &   --         &   $\le$0.02    \\
 05251$-$1244   &   0.09    $\pm$   0.03    &   0.028   $\pm$   0.009   &   0.012   $\pm$   0.009   &   0.006   $\pm$   0.009   &   0.28    $\pm$   0.08    &   0.023   $\pm$   0.009   &   0.014   $\pm$   0.009   &   $\le$0.04    &   $\le$0.02    \\
 05341$+$0852   &   $\le$0.06    &   $\le$0.04    &   --         &   ?           &   ?           &   0.052   $\pm$   0.009   &   ?           &   0.050   $\pm$   0.009   &   0.12    $\pm$   0.02    \\
 06530$-$0213   &   --         &   --         &   ?           &   ?           &   1.69    $\pm$   0.08    &   0.020   $\pm$   0.006   &   0.556   $\pm$   0.008   &   --         &   --         \\
 07134$+$1005   &   0.039   $\pm$   0.006   &   0.014   $\pm$   0.004   &   0.011   $\pm$   0.004   &   ?           &   $\le$0.09    &   $\le$0.003   &   0.112   $\pm$   0.009   &   --         &   $\le$0.01    \\
 08005$-$2356   &   $\le$0.04    &   0.035   $\pm$   0.009   &   0.024   $\pm$   0.009   &   $\le$0.01    &   ?           &   $\le$0.009   &   $\le$0.01    &   $\le$0.02    &   ?           \\
 08143$-$4406   &   --         &   --         &   0.045   $\pm$   0.004   &   $\le$0.005   &   1.23    $\pm$   0.03    &   0.052   $\pm$   0.002   &   0.228   $\pm$   0.005   &   0.061   $\pm$   0.008   &   0.202   $\pm$   0.009   \\
 08544$-$4431   &   0.37    $\pm$   0.01    &   ?           &   0.048   $\pm$   0.004   &   0.014   $\pm$   0.004   &   0.58    $\pm$   0.03    &   0.072   $\pm$   0.004   &   0.170   $\pm$   0.003   &   0.072   $\pm$   0.006   &   0.161   $\pm$   0.007   \\
 12175$-$5338   &   0.12    $\pm$   0.01    &   0.014   $\pm$   0.006   &   0.017   $\pm$   0.005   &   0.026   $\pm$   0.004   &   0.29    $\pm$   0.02    &   $\le$0.004   &   0.034   $\pm$   0.004   &   --         &   $\le$0.008   \\
 16594$-$4656   &   --         &   --         &   0.075   $\pm$   0.007   &   0.057   $\pm$   0.005   &   1.19    $\pm$   0.04    &   0.082   $\pm$   0.006   &   0.204   $\pm$   0.007   &   0.072   $\pm$   0.008   &   0.164   $\pm$   0.007   \\
 17086$-$2403   &   0.29    $\pm$   0.07    &   $\le$$\pm$0.06    &   $\le$0.04    &   $\le$0.02    &   $\le$0.1 &   $\le$0.04    &   0.04    $\pm$   0.03    &   $\le$0.1 &   $\le$0.05    \\
 17097$-$3210   &   --         &   --         &   0.030   $\pm$   0.006   &   0.019   $\pm$   0.004   &   0.13    $\pm$   0.04    &   0.041   $\pm$   0.004   &   0.079   $\pm$   0.005   &   0.050   $\pm$   0.006   &   0.107   $\pm$   0.006   \\
 17150$-$3224   &   --         &   --         &   0.023   $\pm$   0.007   &   ?           &   1.10    $\pm$   0.06    &   0.027   $\pm$   0.007   &   0.200   $\pm$   0.006   &   0.086   $\pm$   0.009   &   0.327   $\pm$   0.007   \\
 17245$-$3951   &   --         &   --         &   $\le$0.007   &   ?           &   0.93    $\pm$   0.06    &   0.025   $\pm$   0.006   &   0.065   $\pm$   0.009   &   0.055   $\pm$   0.008   &   0.190   $\pm$   0.007   \\
 17395$-$0841   &   0.20    $\pm$   0.07    &   0.07    $\pm$   0.03    &   $\le$0.03    &   0.06    $\pm$   0.03    &   0.65    $\pm$   0.09    &   0.040   $\pm$   0.009   &   0.20    $\pm$   0.02    &   $\le$0.06    &   0.165   $\pm$   0.065   \\
 17423$-$1755   &   0.40    $\pm$   0.04    &   0.05    $\pm$   0.03    &   $\le$0.06    &   0.027   $\pm$   0.009   &   ?           &   $\le$0.03    &   0.12    $\pm$   0.02    &   $\le$0.08    &   ?           \\
 17436$+$5003   &   ?           &   $\le$0.003   &   0.007   $\pm$   0.003   &   0.005   $\pm$   0.003   &   $\le$0.02    &   0.010   $\pm$   0.003   &   ?           &   --         &   ?           \\
 18025$-$3906   &   0.034   $\pm$   0.009   &   0.058   $\pm$   0.009   &   $\le$0.02    &   $\le$0.005   &   $\le$0.05    &   0.020   $\pm$   0.006   &   0.085   $\pm$   0.007   &   0.032   $\pm$   0.009   &   ?           \\
 18062$+$2410   &   ?       0.02    &   0.03    $\pm$   0.02    &   $\le$0.01    &   $\le$0.01    &   $\le$0.04    &   $\le$0.01    &   $\le$0.01    &   0.034   $\pm$   0.009   &   $\le$0.04    \\
   HD 172324    &   0.068   $\pm$   0.004   &   0.049   $\pm$   0.004   &   ?           &   $\le$0.002   &   $\le$0.02    &   $\le$0.004   &   $\le$0.006   &   $\le$0.01    &   $\le$0.007   \\
 19114$+$0002   &   0.29    $\pm$   0.03    &   $\le$0.02    &   0.063   $\pm$   0.004   &   0.033   $\pm$   0.003   &   0.33    $\pm$   0.07    &   0.046   $\pm$   0.002   &   ?           &   0.059   $\pm$   0.006   &   0.105   $\pm$   0.006   \\
 19200$+$3457   &   ?           &   ?           &   ?           &   ?           &   ?           &   ?           &   ?           &   ?           &   $\le$0.07    \\
 19386$+$0155   &   --         &   --         &   --         &   0.042   $\pm$   0.004   &   0.44    $\pm$   0.04    &   0.062   $\pm$   0.006   &   0.138   $\pm$   0.009   &   0.075   $\pm$   0.009   &   0.134   $\pm$   0.008   \\
 19500$-$1709   &   0.058   $\pm$   0.006   &   0.046   $\pm$   0.004   &   $\le$0.003   &   0.025   $\pm$   0.002   &   0.23    $\pm$   0.02    &   0.009   $\pm$   0.004   &   0.069   $\pm$   0.004   &   --         &   0.040   $\pm$   0.007   \\
 20000$+$3239   &   0.50    $\pm$   0.03    &   ?           &   ?           &   0.074   $\pm$   0.009   &   1.63    $\pm$   0.09    &   0.026   $\pm$   0.009   &   ?           &   --         &   0.32    $\pm$   0.02    \\
 20462$+$3416   &   0.16    $\pm$   0.02    &   0.063   $\pm$   0.009   &   0.030   $\pm$   0.009   &   0.034   $\pm$   0.007   &   0.59    $\pm$   0.04    &   0.038   $\pm$   0.009   &   0.109   $\pm$   0.009   &   --         &   0.06    $\pm$   0.02    \\
 22023$+$5249   &   0.38    $\pm$   0.02    &   0.10    $\pm$   0.02    &   0.013   $\pm$   0.009   &   0.051   $\pm$   0.007   &   0.85    $\pm$   0.07    &   0.019   $\pm$   0.009   &   0.130   $\pm$   0.009   &   0.041   $\pm$   0.009   &   0.12    $\pm$   0.02    \\
 22223$+$4327   &   0.035   $\pm$   0.009   &   ?           &   ?           &   $\le$0.005   &   0.27    $\pm$   0.03    &   0.005   $\pm$   0.006   &   ?           &   --         &   ?           \\
 22272$+$5435   &   ?           &   ?           &   ?           &   $\le$0.02    &   ?           &   $\le$0.04    &   ?           &   --         &   ?           \\
 23304$+$6147   &   0.37    $\pm$   0.02    &   ?           &   ?           &   0.110   $\pm$   0.009   &   0.90    $\pm$   0.07    &   0.044   $\pm$   0.009   &   ?           &   --         &   ?           \\
\hline\end{tabular}}
\smallskip
 ?: Contamination by atmospheric stellar lines or poor S/N;   {--:  spectral range not covered}. 
\end{table}