@article{JMLR:v10:vanderweele09a,
  author  = {Tyler J. VanderWeele and James M. Robins},
  title   = {Properties of Monotonic Effects on Directed Acyclic Graphs},
  journal = {Journal of Machine Learning Research},
  year    = {2009},
  volume  = {10},
  number  = {24},
  pages   = {699--718},
  url     = {http://jmlr.org/papers/v10/vanderweele09a.html}
}