diff --git a/README b/README
index e4d56e8..bc82009 100644
--- a/README
+++ b/README
@@ -14,7 +14,9 @@ some kind of TeX package, like texlive
 
 TO RUN UTT PROGRAMS YOU WILL NEED:
 
-perl module File::HomeDir
+perl modules:
+     File::HomeDir
+     Parse::RecDescent (dgp grammar compilation)
 
 INSTALLATION