Velocities of lines in IUE spectra folded in phase with (P_S, T_S) as listed in Table 4. First row: set 1995; second row: set 1992; third row: set 1988. The spectral features that are plotted are labeled in the first row according to the naming convention given in Table A.1 (Col. 3). They correspond to the following: Col. 1: 1270e (black), HeIIr (magenta), FeVpsudo (cyan); Col. 2: HeIIa (red), NIVa (blue); Col. 3: 1226n (magenta), 1371e (cyan), HeIIb (red); Col. 4: NIVe (blue), NVe (green); Col. 5: NIVnn (black), NIVn (magenta), CIVe+35 km s⁻¹ (cyan), HeIIe +35 km s⁻¹ (blue), NIV]+35 km s⁻¹ (green), 1270n-35 km s⁻¹ (red).