diff --git a/extra/benchmark/spectral-norm/spectral-norm.factor b/extra/benchmark/spectral-norm/spectral-norm.factor
index 0d683d65fb..70489456e4 100644
--- a/extra/benchmark/spectral-norm/spectral-norm.factor
+++ b/extra/benchmark/spectral-norm/spectral-norm.factor
@@ -1,3 +1,6 @@
+! Copyright (C) 2008, 2010 Slava Pestov.
+! See http://factorcode.org/license.txt for BSD license.
+!
 ! Factor port of
 ! http://shootout.alioth.debian.org/gp4/benchmark.php?test=spectralnorm&lang=all
 USING: alien.c-types io kernel math math.functions math.parser