@article{vonHippel:2009K8,
  author = "von Hippel, Georg",
  title = "{Perturbative improvement with HISQ fermions: the gluon action at $O(N_f \alpha_s a^2)$ }",
  doi = "10.22323/1.066.0046",
  journal = "PoS",
  year = 2009,
  volume = "LATTICE 2008",
  pages = "046"
}