1Tal J Haddad S,Gordon N.Heterotopic Pregnency after induction and assisted reproductive technologies: a literature review from 1971 to 1993[].Fertility and Sterility.1996
2Knutzen V,McNamee PI,Stratton CJ,et al.Mock embryo transfer in the early lutealy phase, the cycle before in vitro fertilization and embryo tranfer: a descriptive study[].Fertility and Sterility.1992
3Ian S,Tummon M,Nancy A,et al.Transferring more embryo increase risk of heterotopic Pregnancy[].Fertility and Sterility.1994