1. Establishing a human chorionic gonadotropin cutoff to guide methotrexate treatment of ectopic pregnancy: a systematic review 
Seema Menon, M.D., John Colins, M.D., Kurt T. Barnhart, M.D., M.S.C.E. 
Fertility and Sterility 
Volume 87, Issue 3, Pages (March 2007)
DOI: /j.fertnstert
Copyright © 2007 American Society for Reproductive Medicine Terms and Conditions

2. FIGURE 1 Relationship between hCG levels and failure rates.
Menon. Improving methotrexate treatment success. Fertil Steril 2007.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2007 American Society for Reproductive Medicine Terms and Conditions