@article{walck_characterization_2001,
  author = {Walck, Scott N. and Hansell, Nathan C.},
  doi = {10.1088/0143-0807/22/4/309},
  journal = {European Journal of Physics},
  month = jul,
  number = {4},
  pages = {343},
  title = {Characterization and visualization of the state and entanglement of two spins},
  volume = {22},
  year = {2001},
}