RT Journal Article SR Electronic T1 Practical Contraception JF The Journal of the Royal College of General Practitioners JO J R Coll Gen Pract FD British Journal of General Practice SP 931 OP 931 VO 26 IS 173 A1 John Lloyd A1 Margaret Lloyd YR 1976 UL http://bjgp.org/content/26/173/931.2.abstract AB