diff --git a/Data Structures/data_structures.hpp b/Data Structures/data_structures.hpp
index 1c6d1f0..3399693 100644
--- a/Data Structures/data_structures.hpp	
+++ b/Data Structures/data_structures.hpp	
@@ -1,3 +1,6 @@
+// ver: 0.3
+
 #include "sl_list.hpp"      // Includes node.hpp, <cstddef>, <stdexcept>     
 #include "dl_list.hpp"      // Includes double_node.hpp, <cstddef>, <stdexcept>
-#include "bst.hpp"
\ No newline at end of file
+#include "bst.hpp"
+#include "stack.hpp"
\ No newline at end of file