2FGL J0616.6+2425 has been associated to the [[*WISE*]{}]{}  source J061609.79+241911.0, that belongs to class B with a low association confidence estimated on 5465 [[*WISE*]{}]{} sources in the region of comparison. The 2FGL source 2FGL JJ0312.8+2013 has a [[*WISE*]{}]{} class C source associated following our procedure, with a lower confidence of finding a similar source in a region of comparison where there are 512 [[*WISE*]{}]{} sources.

Within the 313 UGS analyzed there are 14 sources that have a variability index [@abdo11] higher than the value of 41.6 corresponding to the 99% of confidence that the source is variable. It is worth noting that 13 out of these 14 variable UGSs have been successfully associated here with a $\gamma$-ray blazar candidate, strongly supporting the blazar nature.

[|lrlcccc|]{} 2FGL & Sources & [[*WISE*]{}]{}  & $s_b$ & $s_q$ & class & $\pi$\
name & in SR & name & & &\
J0038.8+6259 & 791 & J003818.70+630605.2 & 0.89 & 0.99 & A & 2/830\
J0616.6+2425 & 6021 & J061623.95+241809.2 & — & 0.57 & B & 1/5465\
J0312.8+2013 & 453 & J031223.00+200749.5 & 0.19 & 0.15 & C & 1/512\

\[tab:example\]

The entire list of the UGSs analyzed can be found in Table 2. 