diff --git a/doc/BH_ref_guide/BH_lang.tex b/doc/BH_ref_guide/BH_lang.tex
index 5b3e46c8..5383cd4f 100644
--- a/doc/BH_ref_guide/BH_lang.tex
+++ b/doc/BH_ref_guide/BH_lang.tex
@@ -2729,8 +2729,9 @@ \subsection{The ``size'' types}
 The second line binds {\te{logWPlusOne}} to the integer value
 corresponding to {\te{n}}.
 
+{\index{stringOf@\te{stringOf} (``function'' of string types)}}
 A ``function'' {\te{stringOf}} is also available to get the string value
-of a type-level string.  Example:
+of a type-level string.
 \begin{verbatim}
  type MyString = "Hello, world!"
  x :: String