Ratios of integrated intensities of ¹²CO (blue) and ¹³CO (purple) J = 2–1 and J = 1–0 and infrared emission (12, 25, and 60 μm) in binary post-AGB stars. Blue and red lines represent the averaged values for O- and C-rich AGB CSEs. Sources are are ordered by increasing outflow dominance and enumerated as follows: a – HR 4049, b – DY Ori, 1 – AC Her, 2 – Red Rectangle, 3 – 89 Her, 4 – HD 52961, 5 – IRAS 19157–0257, 6 – IRAS 18123+0511, 7 – IRAS 19125+0343, 8 – AI CMi, 9 – IRAS 20056+1834, and 10 – R Sct. Souces a and b are not included in this mm-wave survey. Sources 1, 2, a, and b are disk-dominated binary post-AGB stars, sources 6 to 10 are outflow-dominated, and sources 3, 4, and 5 are intermediate cases. We note the broad range (on a logarithmic scale) of intensity ratios. We find uncertainties less than ~10% in these ratios, which are basically dominated by that of the integrated intensity of CO (see Bujarrabal et al. 2013a).