@misc{9562,
  author = {R. Platt and J. Delaney and S. Suissa},
  title = {The positivity assumption and marginal structural models: the example of warfarin use and risk of bleeding},
  year = {2012},
  journal = {Eur J Epidemiol},
  volume = {27},
  number = {2},
  pages = {77-83},
  issn = {0393-2990},
  doi = {10.1007/s10654-011-9637-7},
}