@misc{9494,
  author = {H. Booth and A. Prevost and M. Gulliford},
  title = {Validity of smoking prevalence estimates from primary care electronic health records compared with national population survey data for England, 2007 to 2011},
  year = {2013},
  journal = {Pharmacoepidemiol Drug Saf},
  volume = {22},
  number = {12},
  pages = {1357-61},
  issn = {1053-8569},
  doi = {10.1002/pds.3537},
}