Correlation between radial velocity values of white dwarfs in SIMBAD and Gaia DR3. Top panel: SIMBAD radial velocity as a function of the corresponding Gaia DR3 value. Bottom panel: absolute value of the difference between the SIMBAD and the Gaia DR3 values divided by the uncertainty in the Gaia DR3 value. The dashed red line signals the 3σ difference. Points in gold signal SIMBAD values from Gaia DR2.