SIMBAD references

We divide some of the observed diffuse interstellar bands (DIBs) into families that appear to have the spectral structure of single species. Three different methods are applied to separate such families, exploring the best approach for future investigations of this type. Starting with a statistical treatment of the data, we found that statistical methods by themselves give insufficient results. Two other methods of data analysis (`averaging equivalent widths' and `investigating the figures with arranged spectrograms') were found to be more useful as tools for finding the spectroscopic families of DIBs. On the basis of these methods, we suggest some candidates as `relatives' of 5780- and 5797-Å bands.