diff --git a/guide/english/network-engineering/osi-layers/index.md b/guide/english/network-engineering/osi-layers/index.md
index 4a7120b98c..748ebbf601 100644
--- a/guide/english/network-engineering/osi-layers/index.md
+++ b/guide/english/network-engineering/osi-layers/index.md
@@ -42,3 +42,6 @@ In the diagram above, to the extreme left is the unit of data that is used in ea
 * _**Layer 6 - Presentation Layer:**_ The presentation layer formats the data to be presented to the application layer. 
 
 * _**Layer 7 - Application Layer:**_ The application layer serves as the window for users and application processes to access network services.
+
+#### More Information:
+* https://www.mheducation.com/highered/product/data-communications-networking-forouzan/M0073376221.html