AGUs (Paper III). From the distributions of the $s_b$ and $s_q$ parameters for the generic IR [[*WISE*]{}]{} sources, we note that 99.9% of them have $s_b<$0.24 and $s_q<$0.38. Then, for the BZBs in the 2FB sample only 6 sources out of 135 have $s_b<$ 0.24, and in the case of the BZQs only 33 sources out of 149 show $s_q$ values lower than 0.38. We also note that 99.0% of the generic IR [[*WISE*]{}]{} sources have $s_b<$0.10 and only 2 BZBs are below this value, while 97.2% of the generic IR [[*WISE*]{}]{} sources together with only 5 BZQs out of 149 have $s_q<$0.14.

The [[*WISE*]{}]{} objects of class A are the most probable blazar counterpart of the unidentified $\gamma$-ray sources, because their WISE colors are more consistent with the [[*WGS*]{}]{}  in both the BZBs and BZQs subregions than the colors of sources of class B or C. Based on the distributions of the $s_b$ and $s_q$ parameters for [[*WISE*]{}]{} sources in random region of the sky, the sources of class A are, as expected, rarer than the sources belonging to the other two classes (see Section \[sec:ugs\] for more details).

The association procedure {#sec:procedure}
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![The position of the region 