@misc{perez2004introduction,
  title={Introduction to Loop Quantum Gravity and Spin Foams},
  author={Alejandro Perez},
  year={2004},
  eprint={gr-qc/0409061},
  archivePrefix={arXiv},
  primaryClass={gr-qc},
  url={https://arxiv.org/abs/gr-qc/0409061}
}