Maximally entangling tripartite protocols for Josephson phase qubits
  We introduce a suit of simple entangling protocols for generating tripartite GHZ and W states in systems with anisotropic exchange interaction g(XX+YY)+g'ZZ. An interesting example is provided by macroscopic entanglement in Josephson phase qubits with capacitive (g'=0) and inductive (0<|g'/g|<0.1) couplings. 
Andrei Galiautdinov and John M. Martinis