diff --git a/guc.c b/guc.c
index d80f1a92..f51a7a54 100644
--- a/guc.c
+++ b/guc.c
@@ -1,8 +1,13 @@
 /*-------------------------------------------------------------------------
  *
- * guc.c
+ * guc.c: guc variable handling of pg_stat_monitor
+ *
+ * Portions Copyright © 2018-2020, Percona LLC and/or its affiliates
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ *
+ * Portions Copyright (c) 1994, The Regents of the University of California
  *
- * Copyright (c) 2008-2018, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
  *	  contrib/pg_stat_monitor/guc.c
diff --git a/hash_query.c b/hash_query.c
index 32164c03..d81179bc 100644
--- a/hash_query.c
+++ b/hash_query.c
@@ -3,7 +3,11 @@
  * hash_query.c
  *		Track statement execution times across a whole database cluster.
  *
- * Copyright (c) 2008-2020, PostgreSQL Global Development Group
+ * Portions Copyright © 2018-2020, Percona LLC and/or its affiliates
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ *
+ * Portions Copyright (c) 1994, The Regents of the University of California
  *
  * IDENTIFICATION
  *	  contrib/pg_stat_monitor/hash_query.c
diff --git a/pg_stat_monitor.c b/pg_stat_monitor.c
index 552162bc..24556311 100644
--- a/pg_stat_monitor.c
+++ b/pg_stat_monitor.c
@@ -3,7 +3,11 @@
  * pg_stat_monitor.c
  *		Track statement execution times across a whole database cluster.
  *
- * Copyright (c) 2008-2018, PostgreSQL Global Development Group
+ * Portions Copyright © 2018-2020, Percona LLC and/or its affiliates
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ *
+ * Portions Copyright (c) 1994, The Regents of the University of California
  *
  * IDENTIFICATION
  *	  contrib/pg_stat_monitor/pg_stat_monitor.c
diff --git a/pg_stat_monitor.h b/pg_stat_monitor.h
index 274dfbc0..85295d2c 100644
--- a/pg_stat_monitor.h
+++ b/pg_stat_monitor.h
@@ -1,3 +1,19 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_stat_monitor.h
+ *		Track statement execution times across a whole database cluster.
+ *
+ * Portions Copyright © 2018-2020, Percona LLC and/or its affiliates
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ *
+ * Portions Copyright (c) 1994, The Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  contrib/pg_stat_monitor/pg_stat_monitor.h
+ *
+ *-------------------------------------------------------------------------
+ */
 #ifndef __PG_STAT_MONITOR_H__
 #define __PG_STAT_MONITOR_H__