Concurrence and entanglement entropy in a dimerised spin-1/2 two-leg ladder S. Nemati, S. Batebi and S. Mahdavifar Eur. Phys. J. B, 83 3 (2011) 329-335 Published online: 12 October 2011 DOI: 10.1140/epjb/e2011-20412-7