@misc{indiciaea2efbfdda444,
  title = {Second-harmonic generation at simple metal surfaces.},
  author = {A Liebsch and WL Schaich},
  year = {1989},
  doi = {10.1103/physrevb.40.5401},
  url = {https://pubmed.ncbi.nlm.nih.gov/9992570/},
  note = {Source identifier: 9992570}
}