diff --git a/src/os/unix/ngx_thread.h b/src/os/unix/ngx_thread.h
index 69d3c34..f78a7c0 100644
--- a/src/os/unix/ngx_thread.h
+++ b/src/os/unix/ngx_thread.h
@@ -1,3 +1,9 @@
+
+/*
+ * Copyright (C) 2002-2004 Igor Sysoev
+ */
+
+
 #ifndef _NGX_THREAD_H_INCLUDED_
 #define _NGX_THREAD_H_INCLUDED_