diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 <!-- -*- Markdown -*- -->
 
+## 0.8.0.2
+
+- Update documentation.
+
 ## 0.8.0.1
 
 - Fix build-depends.
diff --git a/relational-query.cabal b/relational-query.cabal
--- a/relational-query.cabal
+++ b/relational-query.cabal
@@ -1,5 +1,5 @@
 name:                relational-query
-version:             0.8.0.1
+version:             0.8.0.2
 synopsis:            Typeful, Modular, Relational, algebraic query engine
 description:         This package contiains typeful relation structure and
                      relational-algebraic query building DSL which can
diff --git a/src/Database/Relational/Query/Monad/Class.hs b/src/Database/Relational/Query/Monad/Class.hs
--- a/src/Database/Relational/Query/Monad/Class.hs
+++ b/src/Database/Relational/Query/Monad/Class.hs
@@ -41,9 +41,11 @@
   -- | Add restriction to last join.
   restrictJoin :: Projection Flat (Maybe Bool) -- ^ 'Projection' which represent restriction
                -> m ()                         -- ^ Restricted query context
+  {- Haddock BUG? -}
+  -- | Join sub-query with place-holder parameter 'p'. query result is not 'Maybe'.
   query' :: Relation p r
          -> m (PlaceHolders p, Projection Flat r)
-
+  -- | Join sub-query with place-holder parameter 'p'. Query result is 'Maybe'.
   queryMaybe' :: Relation p r
               -> m (PlaceHolders p, Projection Flat (Maybe r))