diff --git a/README.md b/README.md
index 486b3d0..6ac1be5 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ older versions might be available on a dedicated branch.
 * [ml_yacc_lib.thy](ml_yacc_lib.thy) provides Isabelle support for parser 
   generated by ml-yacc (part of sml/NJ).
 
-* [fxp.thyy](fxp.thyy) provides Isabelle support for The Functional XML
+* [fxp.thy](fxp.tyy) provides Isabelle support for The Functional XML
   Parser (fxp).
 
 ## Authors