The network of concepts in written texts S. M.G. Caldeira, T. C. Petit Lobão, R. F.S. Andrade, A. Neme and J. G.V. Miranda Eur. Phys. J. B, 49 4 (2006) 523-529 Published online: 31 March 2006 DOI: 10.1140/epjb/e2006-00091-3