\begin{table}%t3
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%\centering
\par
\caption{\label{tab:literature_obs}Literature sources for the sub-mm/mm data. } 
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\begin{tabular}{cc}
\hline \hline \noalign{\smallskip}
$\lambda$ (mm) & Source references \\
\hline
0.450  &  1   \\
0.600  &  2, 3  \\
0.624  &  4   \\
0.769  &  4    \\
0.800  &  2, 3   \\
0.850  &  1, 5   \\
0.880  &  5   \\
1.056  &  4   \\
1.100  &  2, 3  \\
1.200  &  6 \\
1.300  &  1, 7, 8, 9, 10 \\
1.330  &  5 \\
2.000  &  2, 11 \\
2.700  &  7, 8, 12, 13 \\
3.100  &  8 \\
3.400  &  9, 14  \\
7.000  &  15\\
\hline
\end{tabular}
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\tablebib{(1) Andrews \& Williams (\cite{And05}); (2)~Mannings \& Emerson (\cite{Man94}); (3)~Adams et~al. (\cite{Ada90}); (4)~Beckwith \& Sargent (\cite{Bec91}); (5)~Andrews \& Williams (\cite{And07}); (6)~Althenoff et~al. (\cite{Alt94}); (7)~Dutrey et~al. (\cite{Dut96}); (8)~Jensen et~al. (\cite{Jen96}); (9)~Koerner et~al. (\cite{Koe95}); (10)~Isella et~al. (\cite{Ise09}); (11)~Kitamura et~al. (\cite{Kit02}); (12)~Mundy et~al. (\cite{Mun96}); (13)~Schaefer et~al. (\cite{Sch09}); (14)~Ohashi et~al. (\cite{Oha96}); (15)~Rodmann et~al. (\cite{Rod06}).}
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\end{table}