Scheme for demonstrating Bell theorem in tripartite entanglement between   atomic ensembles
  We propose an experimentally feasible scheme to demonstrate quantum nonlocality, using Greenberger-Horne-Zeilinger (GHZ) and $W$ entanglement between atomic ensembles generated by a new developed method based on laser manipulation and{} single-photon detection. 
X.-B. Zhou, Y.-S. Zhang and G.-C. Guo