@article{reconfigurableintelligentsurfacesasignal,
  title = {Reconfigurable Intelligent Surfaces: A Signal Processing Perspective With Wireless Applications},
  author = {Emil Björnson and Henk Wymeersch and Bho Matthiesen and Petar Popovski and Luca Sanguinetti and Elisabeth de Carvalho},
  year = {2021},
  eprint = {2102.00742},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2102.00742v2},
}