diff --git a/docs/langs/explicit-substitution/exp/Exp.cic b/docs/langs/explicit-substitution/exp/Exp.cic
index 22a73096..f2eab4ca 100644
--- a/docs/langs/explicit-substitution/exp/Exp.cic
+++ b/docs/langs/explicit-substitution/exp/Exp.cic
@@ -6,6 +6,6 @@ datatype Exp {
 }
 
 class Binding {
-  name: string
+  name: String
   exp: Exp
 }
diff --git a/docs/langs/explicit-substitution/reduce/lookup.cic b/docs/langs/explicit-substitution/reduce/lookup.cic
index 20bb21e0..f75db1f4 100644
--- a/docs/langs/explicit-substitution/reduce/lookup.cic
+++ b/docs/langs/explicit-substitution/reduce/lookup.cic
@@ -1,7 +1,7 @@
 import { Binding, Exp } from "../exp/index.cic"
 
 export function lookup(
-  name: string,
+  name: String,
   bindings: List(Binding),
 ): Maybe(Exp) {
   let found = listFind(