RT Journal Article SR Electronic T1 Dennis Vernon Duckworth, MB, BS, FRCGP JF The Journal of the Royal College of General Practitioners JO J R Coll Gen Pract FD British Journal of General Practice SP 511 OP 511 VO 30 IS 217 A1 David H. S. Cannon YR 1980 UL http://bjgp.org/content/30/217/511.1.abstract AB