1. Physiological range of human chorionic gonadotropin for support of early human pregnancy 
Craig A.H Richard, Ph.D., Carolyn J Kubik, M.D., Julie A DeLoia, Ph.D. 
Fertility and Sterility 
Volume 76, Issue 5, Pages (November 2001)
DOI: /S (01)

2. Figure 1
A scattergram distribution of all the hCG values for days 12–16 post-OR for successful singleton birth outcomes. Numbers in parentheses are the highest and lowest values for each day.
Richard. Early pregnancy range of hCG. Fertil Steril 2001.
Fertility and Sterility  , DOI: ( /S (01) )

3. Figure 2
Highest and lowest quartile mean values for days 12–16 post-OR. Displayed error bars are SDs. Mean values of all data points for each day are shown for reference and comparison.
Richard. Early pregnancy range of hCG. Fertil Steril 2001.
Fertility and Sterility  , DOI: ( /S (01) )

4. Figure 3
Scattergram distribution displaying the range of doubling times for the 48-hour periods during days 12–14, days 13–15, and days 14–16. The highest and lowest values for each 48-hour data set are displayed in parentheses. Underlined values are mean values for each 48-hour data set, and location of mean is indicated by bar symbol.
Richard. Early pregnancy range of hCG. Fertil Steril 2001.
Fertility and Sterility  , DOI: ( /S (01) )