Clustering of the optical-afterglow luminosities of long gamma-ray burstsM. Nardini, G. Ghisellini, G. Ghirlanda, F. Tavecchio, C. Firmani and D. LazzatiA&A, 451 3 (2006) 821-833DOI: https://doi.org/10.1051/0004-6361:20054085
