Dedman, D;
Cabecinha, M;
Williams, R;
Evans, SJW;
Bhaskaran, K;
Douglas, IJ;
(2020)
Approaches for combining primary care electronic health record data from multiple sources: a systematic review of observational studies.
BMJ Open
, 10
(10)
, Article e037405. 10.1136/bmjopen-2020-037405.