@misc{W3037256833,
  author = {Vlatko Vedral and Martin B. Plenio and M. A. Rippin and P. L. Knight},
  title = {Quantifying Entanglement},
  year = {1997},
  howpublished = {Physical Review Letters},
  doi = {https://doi.org/10.1103/physrevlett.78.2275}
}