diff --git a/charts-tests.factor b/charts-tests.factor
index 51e4c048b1..83d25591da 100644
--- a/charts-tests.factor
+++ b/charts-tests.factor
@@ -1,4 +1,4 @@
 ! Copyright (C) 2017 Alexander Ilin.
-
+! See http://factorcode.org/license.txt for BSD license.
 USING: tools.test charts ;
 IN: charts.tests
diff --git a/charts.factor b/charts.factor
index 132a106de3..306f8ab855 100644
--- a/charts.factor
+++ b/charts.factor
@@ -1,5 +1,5 @@
 ! Copyright (C) 2016-2017 Alexander Ilin.
-
+! See http://factorcode.org/license.txt for BSD license.
 USING: kernel ui.gadgets ;
 IN: charts
 
diff --git a/lines/lines-tests.factor b/lines/lines-tests.factor
index 24301d3187..663592498b 100644
--- a/lines/lines-tests.factor
+++ b/lines/lines-tests.factor
@@ -1,5 +1,5 @@
 ! Copyright (C) 2017 Alexander Ilin.
-
+! See http://factorcode.org/license.txt for BSD license.
 USING: kernel math sequences tools.test charts.lines
 charts.lines.private ;
 IN: charts.lines.tests
diff --git a/lines/lines.factor b/lines/lines.factor
index b00ea8eafc..03564e8367 100644
--- a/lines/lines.factor
+++ b/lines/lines.factor
@@ -1,5 +1,5 @@
 ! Copyright (C) 2016-2017 Alexander Ilin.
-
+! See http://factorcode.org/license.txt for BSD license.
 USING: accessors arrays binary-search charts combinators
 combinators.short-circuit fry kernel locals make math math.order
 math.statistics math.vectors namespaces opengl opengl.gl