Observed spectrum and MADCUBA LTE best fit shown in black and red, respectively, in each panel. The spectra are shown as brightness temperature vs. rest frequency. In the upper-left corner and at the bottom of each panel, the molecular species and the corresponding line employed in the fit are indicated (see Table 2). Each raw refers to one of the four mm sources: B, A1, A2 and A3, from top to bottom panels, respectively.