\begin{table}%T2
\caption{Parameters and their references used in the analyses.}
\label{param}
%\centering
\small
\begin{tabular}{p{5cm}p{2cm}p{14cm}}
\hline
\hline
Parameter & Label on the SOM & References \\
\hline
%%%%%%%%%%%%%%%%%%%%%
Optical identification & ID & \citet{odea05,orienti06a,stan93,devr97,jeya00,mtt01,snellen02,imp91,hb93,stan98}; NED; \citet{xia06,dalla00,snellen95,aug06,xia05,mtt00,wil92} \\
Redshift & $z$ & \citet{vv03,hb93,odea96,jeya00,devr97}; NED; \citet{stan93,odea05,imp91,tin06,dalla00,stan98,lab07,ori06b,devr07,xia05,snellen95,xia06,imta90,imp91}
\\
Size & Size\_kpc & \citet{orienti06a, ob97, aug06, gur99, jeya00, xia06, xia05, stan01, gup06, dalla98, lab07, bes99} \\
Power at 5 GHz & P\_5~GHz & Calculated as described in the text \\
Optical polarization & p\_opt & \citet{imta90,mar96,odea98,wil92,vis98,imp91,fug88} \\
Radio polarization & p\_radio & \citet{aah03,zuk99,step95,hl06,ricci04} \\
$B$ magnitude &  & \citet{vv03,sie98,lab07,dalla02} \\
$V$ magnitude &  & \citet{dalla02,vv03,obs91,bar05,imta90,imp91,hb93,lab07,dalla02,wil92} \\
$R$ magnitude &  & \citet{dalla02,stan93,odea96,obs91,tin06,vv03,lab07} \\
$I$ magnitude &  & \citet{stan93,devr95,dalla02,gua06,xia05,devr00} \\
$V-R$ colour & $V-R$ & \citet{dalla02}, and calculated values\\
$B-V$ colour & $B-V$ & \citet{vv03}, and calculated values\\
$U-B$ colour & $U-B$ & \citet{vv03}, and calculated values \\
VLBI morphology & -- & \citet{orienti06a,obs91,aug06,jeya00,xia05,fc97,xia06,dalla98,gugli05,lis02} \\
$R-I$ colour & $R-I$ & \citet{odea96, obs91} \\
Hydrogen column density in X-rays & N\_H\_X & \citet{gua06,sie98,vink06,elv94,blo99,siemi03} \\
Power law slope in X-rays & Gamma & \citet{gua06,sie98,vink06,siemi03} \\
Hydrogen column density 21~cm & N\_H\_21 & \citet{ori06b,gup06,pih03} \\
$O-E$ colour & $O-E$ & \citet{snellen02b} \\
Variability index & vi & Calculated as described in the text \\
Number of observations & N\_vi & Calculated as described in the text \\
Rest frame turnover frequency & nu\_peak,rest & Calculated as described in the text \\
Optically thick spectral index & alpha\_b & Calculated as described in the text \\
Optically thin spectral index & alpha\_a & Calculated as described in the text \\
Curvature & Curvature & Calculated as described in the text \\
Symmetry & Symmetry & Calculated as described in the text \\
Width of the spectrum & {\it FWHM} & Calculated as described in the text \\
\hline 
\end{tabular} %for print version
\end{table}