diff --git a/constraints.tex b/constraints.tex
index 5bece6f..56df85b 100644
--- a/constraints.tex
+++ b/constraints.tex
@@ -443,6 +443,7 @@ Our constraint generation rules have the form:
 $\mtypeEnvironment \vdash \expr{e} : \tv{a} \implies C$,
 that given a method environment $\mtypeEnvironment$ and an expression $\expr{e}$ with type $\tv{a}$ generates the constraint set $C$.
 
+%Inference-rule in the style of: https://dl.acm.org/doi/pdf/10.1145/345099.345100
 \begin{mathpar}
   \inferrule[Method-Cons]{
       \mtypeEnvironment \vdash \expr{e} : \tv{e} \implies C \\