Visible and near-infrared spectra of the three middle and outer main belt asteroids (MOVs) studied in this work (grey points). The blue and brown curves represent average spectra corresponding to the V-type and S-type taxonomic classes, respectively, and their standard deviation as defined by DeMeo et al. (2009). The green curves are fourth-order polynomial fits to the maxima and the minima used to compute Slope I and II (straight black lines).