Inconsistent Fe II lines in AGN spectra. In the spectrum shown in panel A, all inconsistent Fe II lines are present and assigned to the P+, G+, OL, and H groups of lines. In the spectrum shown in panel B, the H group of inconsistent lines is missing, while in panel C, only the P+ group of inconsistent lines is present. The spectrum shown in panel D has no inconsistent lines. All spectra are shown after the subtracted power-law continuum. The spectra shown in panels belong to objects SDSS J154732.17+102451.2 (A), SDSS J085632.40+504114.0 (B), SDSS J012302.02-024400.3 (C) and SDSS J002332.33-011444.1 (D).