Comparison with literature data, homogenized to the same photometric band and cosmological parameters. Squared point refer to the WINGS median values of the galaxies (including the unknown galaxies) subsample, the triangle to the subsample all objects of galaxies and unknown sources, excluding stars. When fixing the α_b the is coincident in the two cases considered (i.e. population of pure galaxies or galaxies and unknown objects), therefore only one (green) square remains visible. The purple triangle refers to the weighted mean of the population of pure galaxies, derived leaving the bright end slope of the LF free to vary.