diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,1 +1,7 @@
 # moffy
+
+One of the implementation of Monadic Functional Reactive Programming.
+
+[Monadic Functional Reactive Programming](<http://github.com/bitemyapp/papers/blob/master/Monadic Functional Reactive Programming.pdf>)
+
+I'll write the documentation later.
diff --git a/moffy.cabal b/moffy.cabal
--- a/moffy.cabal
+++ b/moffy.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           moffy
-version:        0.1.0.0
+version:        0.1.1.0
 synopsis:       Monadic Functional Reactive Programming
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/moffy#readme>
 category:       Control
@@ -43,7 +43,6 @@
       Control.Moffy.Run
   other-modules:
       Control.Moffy.Event.Lock.Internal
-      Lib
       Paths_moffy
   autogen-modules:
       Paths_moffy
diff --git a/src/Control/Moffy.hs b/src/Control/Moffy.hs
--- a/src/Control/Moffy.hs
+++ b/src/Control/Moffy.hs
@@ -19,7 +19,7 @@
 	-- ** Traverse
 	find, scanl,
 	-- ** Parallel
-	first, at, break, until, indexBy,
+	first, at, atResult, break, until, indexBy,
 	-- ** Copies
 	spawn, parList ) where
 
@@ -57,6 +57,10 @@
 	Sig s es a r -> React s es' r' ->
 	React s (es :+: es') (Either r (Maybe a, r'))
 at = at_ forkThreadId
+
+atResult :: (r -> String) -> (r' -> String) ->
+	(Either r (Maybe a, r')) -> (Either String a)
+atResult m1 m2 = (Left . m1) `either` (\(mx, r) -> maybe (Left $ m2 r) Right mx)
 
 infixl 7 `break`, `until`
 
diff --git a/src/Lib.hs b/src/Lib.hs
deleted file mode 100644
--- a/src/Lib.hs
+++ /dev/null
@@ -1,6 +0,0 @@
-module Lib
-    ( someFunc
-    ) where
-
-someFunc :: IO ()
-someFunc = putStrLn "someFunc"