S H Okamoto, D L Healy, L M Morrow, P A Rogers, A O Trounson, E C Wood et al
Okamoto S H, Healy D L, Morrow L M, Rogers P A, Trounson A O, Wood E C et al.
Predictive value of plasma human chorionic gonadotrophin beta subunit in diagnosing ectopic pregnancy after in vitro fertilisation and embryo transfer.
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doi:10.1136/bmj.294.6573.667