diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 67a37f2..8f56b0a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -9,3 +9,7 @@ For now, read
 https://github.com/JuliaLang/julia/blob/master/CONTRIBUTING.md
 
 
+Use of UTF-8 characters in program code
+---------------------------------------
+We have decided not to use them. See issue #18.
+