@Article{Barton1992a,
  author       = {Russell R. Barton},
  title        = {Computing Forward Difference Derivatives in Engineering Optimization},
  volume       = {20},
  number       = {3},
  pages        = {205--224},
  year         = {1992},
  doi          = {10.1080/03052159208941281},
  journal = {Engineering Optimization},
}