SIMBAD references

We present a method based on the non-linear behaviour of neural network for the identification of the early-type population in the cores of galaxy clusters. A Kohonen Self Organising Map applied on a three-colour photometric catalogue of objects enabled us to select in each passband the elliptical galaxies. We measured in this way the luminosity function of the E/S0 galaxies selected in this way. Such luminosity functions show peculiarities which disfavour the hypothesis of its universality often claimed for rich clusters and that can be related to the past dynamical history of the cluster as a whole.