diff --git a/std/jule/sema/symbol.jule b/std/jule/sema/symbol.jule
index b962cc917..ba076557b 100644
--- a/std/jule/sema/symbol.jule
+++ b/std/jule/sema/symbol.jule
@@ -37,6 +37,13 @@ use std::jule::lex::{Token, TokenId, TokenKind}
 use strings for std::strings
 
 // Stack for symbol references.
+// It used by Sema to store necessary references.
+//
+// List of necessary references;
+//  - &FnIns
+//  - &StructIns
+//  - &Trait
+//  - &Var -> Only global ones.
 pub struct ReferenceStack {
     buffer: []any
 }