00331nas a2200145   4500000000100000000000100001008004100002100001500043700001400058700001400072245006800086300001000154490000700164022001400171       2011                            d1 aE. Herrett1 aS. Thomas1 aL. Smeeth00aValidity of diagnoses in the general practice research database  a438-90 v61  a0960-1643