Fig. Distribution of frequency differences Δf = fν - f1 for LMC FO-ν Cepheids and for LMC RRc-BL stars (from Nagy & Kovács 2006). For RRc-BL variables with frequency triplets, only higher side peaks are taken into account. Shaded area marks variables with Pν/P1 = 0.60 - 0.64. [post script]