@techreport{martin15a,
  author =        {Martin, William and Sarro, Federica and Harman, Mark},
  title =         {Causal Impact Analysis Applied to App Releases in {Google Play} and {Windows Phone Store}},
  institution =   {University College London},
  year  =         {2015},
  url   =         {http://www.cs.ucl.ac.uk/fileadmin/UCL-CS/research/Research_Notes/RN_15_07.pdf}
}