diff --git a/rules/S5999/cfamily/rule.adoc b/rules/S5999/cfamily/rule.adoc
index 84cd99ab60..14773f7368 100644
--- a/rules/S5999/cfamily/rule.adoc
+++ b/rules/S5999/cfamily/rule.adoc
@@ -30,6 +30,9 @@ void processAll(D &...data) {
 }
 ----
 
+== Resources
+
+* {cpp} reference - https://en.cppreference.com/w/cpp/thread/scoped_lock[std::scoped_lock]
 
 ifdef::env-github,rspecator-view[]
 '''