Dependence of oscillation periods on n_Brad estimated for the CU Vir model for eigenfunctions from the first to the fourth orders. Different line styles are used for first (red, circle), second (blue, square), third (green, triangle), and fourth (cyan, cross). For comparison, t_cross is indicated by a dotted black line. The constant value (dashed yellow line) corresponds to the oscillation period suggested for CU Vir (67.6 yr).