L_UV (left) and L_{2 − 10 keV} (right), as a function of the rest frame C IV peak velocity shift for the z ≃ 3, T20/C IV, and WISSH (Zappacosta et al. 2020) samples (we excluded two quasars that overlap with our z ≃ 3 sample), and five additional z ≃ 3.2 − 3.7 quasars with available υ_peak (published by Coatman et al. 2017, magenta triangles, we neglected three overlaps with our z ≃ 3 sample). The solid line in the left panel is the C IVυ_peak − L_UV best-fit relation by T20, whilst the one in the right panel is the L_{2 − 10 keV}–C IVυ_peak best-fit relation reported by Zappacosta et al. (2020, see their Table 1). X-ray-weak quasars in T20 (Δα_ox ≤ −0.2) are marked with brown open circles.