RT Journal Article SR Electronic T1 DIAGNOSIS OF PREGNANCY JF The Journal of the Royal College of General Practitioners JO J R Coll Gen Pract FD British Journal of General Practice SP 838 OP 838 VO 25 IS 160 A1 A. P. K. John YR 1975 UL http://bjgp.org/content/25/160/838.3.abstract AB