Density Functional for van der Waals Forces at Surfaces.

@article{Hult1996DensityFF,
  title={Density Functional for van der Waals Forces at Surfaces.},
  author={Hult and C Andersson and Lundqvist and Langreth},
  journal={Physical review letters},
  year={1996},
  volume={77 10},
  pages={2029-2032}
}