\begin{table}%T4
\par
       \caption{\label{bllac_fluxes}The history of the 2$-$10~keV fluxes of 1H1219+301, H1426+428, Markarian~501 and PKS~0548-322 as observed by past X-ray missions.}
            %\centerline
{
         \begin{tabular}{p{1in}p{1in}p{0.8in}p{0.7in}p{0.6in}p{1.7in}}
            \hline\hline
            \noalign{\smallskip}
Object & Mission & Date & $F_{\rm (2-10)}$$^{{a}}$ & Intrinsic absorption & Reference for flux value\\
            \noalign{\smallskip}
            \hline
            \noalign{\smallskip}
1H1219+301 & XMM-Newton & 11/06/01 & 2.6 & no & Table~\ref{specfits} \\
           & BeppoSAX   & 13/07/99 & 1.5 & no & Costamante et~al. (\cite{costamante}) \\
           & ROSAT      & 18/06/92 & 2.7 & no & Lamer et~al. (\cite{lamer}) \\
           & Einstein   & 05/06/79 & 1.1 & yes$^{{b}}$ & Urry et~al. (\cite{urry}) \\
           & Einstein   & 07/12/78 & 2.5 & no & Urry et~al. (\cite{urry}) \\
            \hline								
H1426+428  & XMM-Newton & 16/06/01 & 2.9 & no & Table~\ref{specfits} \\
           & BeppoSAX   & 08/02/99 & 2.0 & no & Costamante et~al. (\cite{costamante}) \\
           & ASCA       & 06/02/94 & 1.6 & yes & Sambruna et~al. (\cite{sambruna1997_h1}) \\
           & ROSAT      & 24/01/92 & 2.3 & yes & Sambruna et~al. (\cite{sambruna1997_h1}) \\
           & BBXRT      & 09/12/90 & 3.5 & yes & Sambruna et~al. (\cite{sambruna1997_h1}) \\
            \hline								
Markarian~501 & XMM    & 13/07/02 & 4.5 & no & Table~\ref{specfits} \\
           & ASCA      & 26/03/96 & 6.6 & no & Kubo et~al. (\cite{kubo}) \\
           & ROSAT     & 13/08/91 & 2.2 & yes & Fink et~al. (\cite{fink}) \\
           & ROSAT     & 25/02/91 & 1.3 & no & Lamer et~al. (\cite{lamer}) \\
           & Einstein  & 22/08/79 & 2.7 & yes & Ciliegi et~al. (\cite{ciliegi}) \\
           & Einstein  & 01/03/79 & 5.8 & no & Ciliegi et~al. (\cite{ciliegi}) \\
           & Einstein  & 25/01/79 & 1.8 & no & Ciliegi et~al. (\cite{ciliegi}) \\
            \hline								
PKS~0548-322  & XMM      & 03/10/01 & 2.5 & no & Table~\ref{specfits} \\
             & BeppoSAX  & 07/04/99 & 1.5 & no & Costamante et~al. (\cite{costamante}) \\
             & BeppoSAX  & 26/02/99 & 1.8 & no & Costamante et~al. (\cite{costamante}) \\
             & BeppoSAX  & 20/02/99 & 2.3 & no & Costamante et~al. (\cite{costamante}) \\
             & ASCA      & 30/10/93 & 2.8 & yes & Sambruna \& Mushotzky (\cite{sambruna1998_pks0548}) \\
             & ROSAT     & 06/03/92 & 3.8 & yes$^{{c}}$ & Lamer et~al. (\cite{lamer}) \\
             & Einstein  & 06/04/79 & 4.0 & yes & Sambruna \& Mushotzky (\cite{sambruna1998_pks0548}) \\
             & Einstein  & 10/03/79 & 4.5 & no & Ciliegi et~al. (\cite{ciliegi}) \\
\hline
         \end{tabular}}
         \smallskip
\begin{list}{}{}
\item[$^{{a}}$] 2$-$10~keV flux in 10$^{\rm -11}$ erg cm$^{\rm -2}$ s$^{\rm -1}$.
\item[$^{{b}}$] Madejski et~al. (\cite{madejski1991}).
\item[$^{{c}}$] Sambruna \& Mushotzky (\cite{sambruna1998_pks0548}).
\end{list}
  \end{table}