@article{Kennedy:2010bm,
  author = "Kennedy, Anthony D.  and  Clark, Michael A.  and  Silva, Paulo J.",
  title = "{Force-gradient integrators}",
  doi = "10.22323/1.091.0021",
  journal = "PoS",
  year = 2010,
  volume = "LAT2009",
  pages = "021"
}