Entanglement behaviors of two-mode squeezed thermal states in two different environments S.-H. Xiang, K.-H. Song, W. Wen and Z.-G. Shi Eur. Phys. J. D, 62 2 (2011) 289-296 Published online: 18 March 2011 DOI: 10.1140/epjd/e2011-10546-1