Non-full rank bound entangled states satisfying the range criterion
  A systematic method for generating bound entangled states in any bipartite system, with ranks ranging from five to full rank, is presented. These states are constructed by mixing separable states with UPB (Unextendible Product Basis) - generated PPT bound entangled states. A subset of this class of PPT bound entangled states, having less than full rank, is shown to satisfy the range criterion [Phys. Lett. A, vol. 232 (1997) 333]. 
Somshubhro Bandyopadhyay, Sibasish Ghosh, Vwani Roychowdhury