Bell inequalities for multipartite qubit quantum systems and their   maximal violation
  We present a set of Bell inequalities for multiqubit quantum systems. These Bell inequalities are shown to be able to detect multiqubit entanglement better than previous Bell inequalities such as Werner-Wolf-Zukowski- Brukner ones. Computable formulas are presented for calculating the maximal violations of these Bell inequalities for any multiqubit states. 
Ming Li and Shao-Ming Fei
quant-ph