Relative entropy of entanglement of a kind of two qubit entangled states
  We in this paper strictly prove that some block diagonalizable two qubit entangled state with six none zero elements reaches its quantum relative entropy entanglement by the a separable state having the same matrix structure. The entangled state comprises local filtering result state as a special case. 
Xiao-yu Chen, Li-min Meng, Li-zhen Jiang, Xiang-jun Li