diff --git a/docs/functions.md b/docs/functions.md
index 6832698..bc42b2d 100644
--- a/docs/functions.md
+++ b/docs/functions.md
@@ -1,4 +1,4 @@
-Functions
+Functions & Methodology
 =======================
 
 ## Functions
@@ -101,4 +101,4 @@ This [recipe 3](https://bodiyang.github.io/Taxcalc-Payroll/recipes/recipe3.html)
 
 It is known that Congressional Budget Office take the offset effect into consideration when producing revenue projections. Taxcalc-Payroll's performance is in line with the CBO's estimation.
 
-As a reference, this [document of budget options](https://www.cbo.gov/budget-options/54805) shows CBO's estimation of revenue change from the rise of Social Security payroll tax rate by 1% (0.5% on each side of employer and employee). Please be noted that this document is produced in 2018. So we need to be aware of the inflation effect when we compare Taxcalc-Payroll's estimation (current year) with this CBO document (2018).
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+As a reference, this [document of budget options](https://www.cbo.gov/budget-options/54805) shows CBO's estimation of revenue change from the rise of Social Security payroll tax rate by 1% (0.5% on each side of employer and employee). Please be noted that this document is produced in 2018. So we need to be aware of the inflation effect when we compare Taxcalc-Payroll's estimation (current year) with this CBO document (2018).