\begin{table}%t5
  \caption{\label{tab:table5}Number of significant harmonic terms in the three rounds of testing$^{a}$.}
\small%\centerline
 {
        \begin{tabular}{lcccccc}
      \hline \hline
      Solution &  & RA &  &  & Dec &  \\
       \hline 
       & 1${\rm st}$ round & 2${\rm nd}$ round & 3${\rm rd}$ round & 1${\rm st}$ round &
 2${\rm nd}$ round & 3${\rm rd}$ round \\
      \hline  
BU6 & 21 & 6 & 6 & ~2 & 1 & 1 \\
BN6 & ~0 & ~0 & ~0 & ~0 & 0 & 0 \\
BT6 & 17 & 9 & 9 & 17 & 5 & 5 \\
BU4 & 23 & 7 & 7 & ~0 & ~0 & ~0 \\
BN4 & ~0 & ~0 & ~0 & ~0 & 0 & 0 \\
BT4 & 17 & 9 & 9 & 17 & 5 & 5 \\
GU6 & 15 & 6 & 6 & ~8 & 3 & 3 \\
GN6 & ~0 & ~0 & ~0 & ~2 & 1 & 1 \\
GT6 & ~9 & 4 & 4 & ~5 & 2 & 2 \\
GU4 & 15 & 6 & 6 & ~8 & 2 & 2 \\
GN4 & ~0 & ~0 & ~0 & ~2 & 1 & 1 \\
GT4 & ~9 & 4 & 4 & ~5 & 2 & 2 \\
SU6 & ~0 & 0 & 0 & ~0 & 0 & 0 \\
SN6 & ~0 & 0 & 0 & ~0 & 0 & 0 \\
ST6 & ~1 & 1 & 1 & ~0 & 0 & 0 \\
SU4 & ~0 & 0 & 0 & ~0 & 0 & 0 \\
SN4 & ~0 & 0 & 0 & ~0 & 0 & 0 \\
ST4 & ~1 & 1 & 1 & ~0 & 0 & 0 \\
\hline 
      \end{tabular}}
\medskip
$^{a}$ Harmonic terms surviving in the three rounds of testing for the most significant ones. The three rounds are explained in the text, and the third round corresponds to the adopted harmonic fit.
All procedure was done independently for the right ascension and declination residuals between the solutions and the ERF radio interferometry positions. The solutions nomenclature is formed by one letter designating the quasar position input catalog, followed by one letter designating the stellar reference frame, and by the codes~$6$ and~$4$ informing whether the algorithm is of the six or four-parameter model.
\end{table}