P_cyc (in years) as a function of the P_rot (in days) on logarithmic scales, with our data represented by red (Q> 0.75) and blue (Q< 0.75) circles, data from Saar & Brandenburg (1999) by black triangles, and data from Lovis et al. (2011) by gray circles. The squares indicate the sources with secondary periods for some stars on the A sequence according to Saar & Brandenburg (1999). The Sun’s magnetic cycle periods of 11.6 yr (black Sun symbol) and 1.1 yr (gray Sun symbol) are also represented. The P_cyc versus P_rot empirical relations (full lines A and I sequences) proposed by Böhm-Vitense (2007) are also displayed. The empirical relations for shorter term stellar magnetic cycle periods (dashed line S sequence) were obtained by shifting the I sequences by a factor of 1/4.