blazars already associated. We also tested our new procedure [*a posteriori*]{} trying to re-associate all the blazars in the 2FB sample and we found that our results are in good agreement with different association procedures.

The application of our association procedure to the UGSs has led to the selection of possible blazar counterparts for 156 of 313 UGSs analyzed.

As also noted in Section \[sec:ugs\], our association procedure provides also interesting information on the sources that do not have a $\gamma$-ray blazar candidates in the SRs as the case of the unidentified $\gamma$-ray source: 2FGL J1446.8$-$4701, recently identified with the pulsar PSR 1446-4701.

Several developments will be considered to improve our association procedure, such as taking into account not only the IR colors, correspondent to flux ratios, but also the IR fluxes as well as the IR-$\gamma$-ray spectral index correlation (Paper II) and the sky distribution of the $\gamma$-ray blazar candidates, once the whole [[*WISE*]{}]{} data archive will be released. Then, it will be also possible to calibrate our association procedure choosing the different thresholds for the $s$ parameters at different Galactic latitudes to take into account of the [[*WISE*]{}]{} background.

Moreover, our association method is complementary to those adopted 