@article{hartnoll2009,
  title={Lectures on holographic methods for condensed matter physics},
  author={Sean A. Hartnoll},
  year={2009},
  journal={Classical and Quantum Gravity},
  doi={10.1088/0264-9381/26/22/224002},
  url={https://doi.org/10.1088/0264-9381/26/22/224002}
}