@misc{W1972907022,
  author = {Fu‐Guo Deng and Xiao-Shu Liu},
  title = {Two-step quantum direct communication protocol using the Einstein-Podolsky-Rosen pair block},
  year = {2003},
  howpublished = {Physical Review A},
  doi = {https://doi.org/10.1103/physreva.68.042317}
}