Kinematical overview of the sample. The intensity-weighted velocity maps (moment 1, square panels) and position-velocity diagrams (PV, vertical panels) of the CS and H₂ CO molecular emission are shown for the sample analyzed in this work along with the continuum emission of Fig. 1. Moment 1 maps are obtained by clipping fluxes below 3σ. PV diagrams are obtained over the disk major axis taking a width as large as the projected gaseous disk size (see Table 3) along the minor axis. The color units of the moment 1 maps are in km s⁻¹, those of the PV diagrams are the same of Fig. 1. The x-axis of the PV diagrams is in km s⁻¹. The symbols in the center of the images indicate the geometrical center of the continuum emission. The beam size is indicated to the bottom-left corner of each panel. The vertical dashed lines indicate the systemic velocities of the system (see Appendix C). All moment 0 and 1 maps have the same angular scale, as indicated in the leftmost column. North is up, east is left.