Radius–luminosity relation for the C IV BLR. The rest-frame time lag from reverberation mapping and the continuum luminosity at 1350 Å are from Kaspi et al. (2021, in blue) and Shen et al. (2024, in green). Fits from Kaspi et al. (2021) are superimposed as continuous lines. The BLR half-light radii measured from microlensing are superimposed in red. Squares show the measurements from this work for J1339 and J1138, and from Hutsemékers et al. (2023) and Savić et al. (2024) for J1004+4112 and Q2237+0305. Diamonds show the measurements from Fian et al. (2023, 2024) for Q0957+561 and J1004+4112.