@misc{breuer2009measure,
  title={Measure for the Non-Markovianity of Quantum Processes},
  author={Heinz-Peter Breuer and Elsi-Mari Laine and Jyrki Piilo},
  year={2009},
  eprint={0908.0238},
  archivePrefix={arXiv},
  primaryClass={quant-ph},
  url={https://arxiv.org/abs/0908.0238}
}