@article{adefinitionandgraphicalrepresentationfor,
  title = {A Definition and Graphical Representation for Causality},
  author = {David Heckerman and Ross D. Shachter},
  year = {2013},
  eprint = {1302.4956},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1302.4956v2},
}