Hyper-Rayleigh scattering in solution.

@article{Clays1991HyperRayleighSI,
  title={Hyper-Rayleigh scattering in solution.},
  author={Clays and Persoons},
  journal={Physical review letters},
  year={1991},
  volume={66 23},
  pages={2980-2983}
}