\begin{table}%t5	
      \caption{Catalogues with spectral indices.\label{tab:spectab}}
      $$
         \begin{tabular}{lrrrr}\hline\hline
{\rm Name} & {\rm Frequency} & {\rm Frequency\ range} &  {\rm Number\ of} & {\rm Ref.} \\
 & {\rm (MHz)} & {\rm (MHz)} & {\rm sources} & \\
\hline
{\rm MITG} & 4850 & 365 & 7559 & (1) \\
{\rm PMN-S} & 4850 & 2700 & 1847 & (2) \\
{\rm AGN-QSO} & 4850 & 2700 & 1155 & (3) \\
{\rm PKS} & 2700 & 5000 & 4150 & (4) \\
{\rm FA87} & 2700 & 4750 & 211 & (5) \\
{\rm 1Jy} & 1400 & 2700--5000 & 299 & (6) \\
{\rm USSR} & 1400 & 150--408 & 313 & (7) \\
{\rm PULSARS} & 1400 & 300--1400 & 227 & (8) \\
{\rm B3}  &   408  & 1400 & 613 & (9)\\\hline
\end{tabular}
      $$
\par
      \smallskip
(1) Drinkwater et~al. (\cite{Drinkwater97}).\\
(2) Wright et~al. (\cite{Wright94}).\\
(3) V\'{e}ron-Cetty \& V\'{e}ron (\cite{VeronCetty03}).\\	
(4) Bennett et~al. (\cite{Bennett86}), Langston et~al. (\cite{Langston90}), Griffith et~al. 
\hspace*{5mm}\mbox{(\cite{Griffith90}, \cite{Griffith91})}.\\
(5) Forkert \& Altschuler (\cite{Forkert87}).\\
(6) K\"{u}hr et~al. (\cite{Kuhr81}).\\
(7) Roettgering et~al. (\cite{Roettgering94}).\\
(8) Lorimer et~al. (\cite{Lorimer95}), Maron et~al. (\cite{Maron00}).\\
(9) Kulkarni et~al. (\cite{Kulkarni90}).\\
\end{table}