Splitting four ensembles of two-qubit quantum information via three Einstein-Podolsky-Rosen pairs W. Zhang, Y. M. Liu, X. F. Yin and Z. J. Zhang Eur. Phys. J. D, 55 1 (2009) 189-195 Published online: 23 June 2009 DOI: 10.1140/epjd/e2009-00180-y