Comparisons of the CO integrated intensity, IRAS 60 µm emission, and bolometric luminosity (Tables B.1 and 2). In the upper and middle panels L_CO is compared with L_{60 µm} and L_bol. In the lower panel the ¹²CO (J = 1−0) main-beam brightness temperature (T_MB) is plotted against the IRAS 60 µm flux after properly scaling T_MB when observed with a telescope other than the IRAM-30 m antenna (see 7.1). The dashed line is the best linear fit to our data; the dotted lines are linear correlations from Nyman et al. (1992) and Bujarrabal et al. (1992) for O-rich AGBs (orange), C-rich AGBs (purple), and pre-PNe (cyan). The colours and shapes of the markers are the same as in Fig. 7.