A generalized preferential attachment model for business firms growth rates - I. Empirical evidenceF. Pammolli, D. Fu, S. V. Buldyrev, M. Riccaboni, K. Matia, K. Yamasaki and H. E. StanleyEur. Phys. J. B, 57 2 (2007) 127-130DOI: https://doi.org/10.1140/epjb/e2007-00133-4