Robust stationary entanglement of two coupled qubits in independent environments M. Scala, R. Migliore, A. Messina and L. L. Sánchez-Soto Eur. Phys. J. D, 61 1 (2011) 199-205 Published online: 14 September 2010 DOI: 10.1140/epjd/e2010-00230-5