diff --git a/sql-words/src/Language/SQL/Keyword/Internal/Type.hs b/sql-words/src/Language/SQL/Keyword/Internal/Type.hs
index 63ee2436..23abb616 100644
--- a/sql-words/src/Language/SQL/Keyword/Internal/Type.hs
+++ b/sql-words/src/Language/SQL/Keyword/Internal/Type.hs
@@ -100,9 +100,11 @@ data Keyword = SELECT | ALL | DISTINCT | ON
              -}
 
 
+-- | Wrap 'DString' into 'Keyword'
 fromDString :: DString -> Keyword
 fromDString =  Sequence
 
+-- | Unwrap 'Keyword' into 'DString'
 toDString :: Keyword -> DString
 toDString = d  where
   d (Sequence ds) = ds