diff --git a/book/chapter-06-gbapp-reference.md b/book/chapter-06-gbapp-reference.md
index 315015c6..60dc0724 100644
--- a/book/chapter-06-gbapp-reference.md
+++ b/book/chapter-06-gbapp-reference.md
@@ -94,6 +94,7 @@ cinst sql-server-management-studio --confirm
 ``` 
 
 npm install -g npm-check-updates
+npm install -g cost-of-modules
 
 ```