RT Journal Article SR Electronic T1 THE SI FOR THE HEALTH PROFESSIONS JF The Journal of the Royal College of General Practitioners JO J R Coll Gen Pract FD British Journal of General Practice SP 633 OP 633 VO 28 IS 195 A1 D. J. Pereira Gray YR 1978 UL http://bjgp.org/content/28/195/633.3.abstract AB