vast majority of classified non-quasars lie outside the [@2010ApJ...708..927K] region.

![image](MQS_fig10.eps){width="15cm"}

![image](MQS_fig11.eps){width="15cm"}

In Figure \[fig:Schmidt\], we make the same comparison between the MQS quasars and the other candidates in the $A$–$\gamma$ variability plane of [@2010ApJ...714.1194S]. We used a cut in this plane to remove more variable sources (shown as contours) other than quasars that we included as we greatly relaxed the DRW selection criteria of [@2010ApJ...708..927K] in these dense stellar fields. A fair number of common variable stars are periodic with the index of the power-law SF of $\gamma < 0.1$. On the other hand, objects with very high amplitude variations are unlikely to be quasars as quasar variability amplitudes on long time-scales are expected to be $A\approx 0.3$ mag (e.g., @2010ApJ...721.1014M). Our simple cut (solid lines) allows higher contamination than that of @2010ApJ...714.1194S [dotted lines], but also returns the higher number of confirmed quasars.

We also examined the distribution of the confirmed MQS quasars and quasar candidates relative to the mid-IR selection criteria of @2009ApJ...701..508K [Figure \[fig:KKO9\]]. The quasars lie in the proposed selection regions confirming the basic principles outlined in [@2009ApJ...701..508K]. The remaining quasar candidates (shown in the left panels) are either quasars with low S/N or contaminating 