@article{forewordacomputableuniverseunderstanding,
  title = {Foreword: A Computable Universe, Understanding Computation and Exploring Nature As Computation},
  author = {Roger Penrose},
  year = {2012},
  eprint = {1205.5823},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/1205.5823v1},
}