RT Journal Article SR Electronic T1 GENERAL-PRACTITIONER OBSTETRICS JF The Journal of the Royal College of General Practitioners JO J R Coll Gen Pract FD British Journal of General Practice SP 696 OP 697 VO 27 IS 184 A1 Michael Thirlwall YR 1977 UL http://bjgp.org/content/27/184/696.abstract AB