1. A method of screening for ectopic pregnancy and its indication;Kadar;Obstet Gynecol,1981
2. Receiver operating characteristic (ROC) curve analysis of the relative efficacy of single and serial chorionic gonadotropin determinations in the early diagnosis of ectopic pregnancy;Kadar;Fertil Steril,1982
3. Plasma and urinary chorionic gonadotropin during early human pregnancy;Marshall;Obstet Gynecol,1968
4. Determination of gestational age by serum concentrations of human chorionic gonadotropin;Lagrew;Obstet Gynecol,1983
5. Discriminatory hCG zone: its use in the sonographic evaluation for ectopic pregnancy;Kadar;Obstet Gynecol,1981