Top panel: orbital period distribution of sdB+WD binaries from the 2nd CE channel. Different colours mark different WD masses (black 0.6 M_⊙, red 0.8 M_⊙, green 1.0 M_⊙, blue 1.2 M_⊙, purple 1.4 M_⊙). The vertical dashed line marks P = 0.05 d. The contribution of thermal energy has not been included (α_th = 0). The solid lines are for α_CE = 0.3 and the dotted ones for α_CE = 1.0. Bottom panel: orbital period distribution of sdB+WD binaries from the CE channel involving more massive main sequence stars (i.e. >2 M_⊙). The values of α_CE and α_th are indicated in the figure (see Fig. 9).