@article{
  author = {E. Bj\"{o}rnson and H. Wymeersch and B. Matthiesen and P. Popovski and L. Sanguinetti and E. de Carvalho},
  year = {2021},
  month = {Feb},
  title = { Reconfigurable Intelligent Surfaces: A Signal Processing Perspective With Wireless Applications},
  URL = {https://arxiv.org/abs/2102.00742},
  journal={Preprint, submitted to IEEE Signal Processing Magazine}
}