RT Journal Article SR Electronic T1 Using the age-sex register to code preventive procedures JF The Journal of the Royal College of General Practitioners JO J R Coll Gen Pract FD British Journal of General Practice SP 105 OP 106 VO 35 IS 271 A1 R.S.L. Thomas YR 1985 UL http://bjgp.org/content/35/271/105.2.abstract AB