diff --git a/rules/gcp_http_lb_rules/gcp_access_attempts_violating_iap_access_controls.yml b/rules/gcp_http_lb_rules/gcp_access_attempts_violating_iap_access_controls.yml
index 5b9c77f04..2ae78e9bd 100644
--- a/rules/gcp_http_lb_rules/gcp_access_attempts_violating_iap_access_controls.yml
+++ b/rules/gcp_http_lb_rules/gcp_access_attempts_violating_iap_access_controls.yml
@@ -3,6 +3,7 @@ Description: GCP Access Attempts Violating IAP Access Controls
 DisplayName: "GCP Access Attempts Violating IAP Access Controls"
 Enabled: true
 Filename: gcp_access_attempts_violating_iap_access_controls.py
+Reference: https://cloud.google.com/iap/docs/concepts-overview
 Severity: Medium
 Tests:
     - ExpectedResult: true