7Galstyan K,Kurzel RB.Serum beta-HCG titers do not predict ectopic pregnancy[J].Int J Fenil Women Med,2006,51(1): 14-16.
8Mavrelos D,Nicks H,Jamil A,et al.Efficacy and safety of a clinical protocol for expectant management of selected women diagnosed with a tubal ectopic pregnancy[J].Ultrasound in Obstetrics & Gynecology,2013,42(1): 102-107.