diff --git a/src/matrix/m_replace.scad b/src/matrix/m_replace.scad
index d52a8cfe..8fb18317 100644
--- a/src/matrix/m_replace.scad
+++ b/src/matrix/m_replace.scad
@@ -1,3 +1,13 @@
+/**
+* m_replace.scad
+*
+* @copyright Justin Lin, 2022
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib3x-m_replace.html
+*
+**/
+
 function m_replace(m, i, j, value) =
     let(
 		rowI = m[i],