Two dimensional histograms of LSP, SF, and MFVF (from top to bottom) values of artificial light curves with β = 2.0 and f_min = 10^-3 d^-1. On the left side histograms are shown for the case of an even sampling of one measurement every 3.37 days while on the right side, the effects of a realistic (uneven) sampling and simulated instrumental noise are visible (see text for details).