diff --git a/lab01.cbp b/lab01.cbp
index d252210..6f8bb55 100644
--- a/lab01.cbp
+++ b/lab01.cbp
@@ -35,6 +35,7 @@
 		</Compiler>
 		<Unit filename="histogram.cpp" />
 		<Unit filename="histogram.h" />
+		<Unit filename="histogram_internal.h" />
 		<Unit filename="main.cpp" />
 		<Unit filename="text.cpp" />
 		<Unit filename="text.h" />