@InCollection{pearl:bar11-r372-jsm,
  author =       "Pearl, J.\ and Bareinboim, E.",
  title =        "External Validity and Transportability:  A Formal Approach",
  booktitle =    "Proceedings of the American Statistical Association, 
		  Joint Statistical Meetings",
  publisher =    "{MIRA} Digital Publishing",
  address =      "Miami Beach, FL",
  year =         2011,
  pages =        "157--171"
}