@misc{9065,
  author = {C. Crooks and J. West and T. Card},
  title = {A comparison of the recording of comorbidity in primary and secondary care by using the Charlson Index to predict short-term and long-term survival in a routine linked data cohort},
  year = {2015},
  journal = {BMJ Open},
  volume = {5},
  number = {6},
  pages = {e007974},
  issn = {2044-6055},
  doi = {10.1136/bmjopen-2015-007974},
}