diff --git a/coroutine-object.cabal b/coroutine-object.cabal
--- a/coroutine-object.cabal
+++ b/coroutine-object.cabal
@@ -1,5 +1,5 @@
 Name:		coroutine-object
-Version:	0.3
+Version:	0.3.0
 Synopsis:       Object-oriented programming realization using coroutine 
 Description: 	Object-oriented programming realization using coroutine 
 License: 	BSD3
@@ -15,16 +15,10 @@
   ghc-options: 	-Wall -funbox-strict-fields -fno-warn-unused-do-bind -fno-warn-orphans
   ghc-prof-options: -caf-all -auto-all
   Build-Depends:   base >4 && <5, 
+                   either >= 3.1, 
                    mtl>2, 
-                   lens >= 2.5,
-                   containers >= 0.4,
-                   transformers >= 0.3, 
-                   transformers-free >= 1.0, 
-                   bytestring >= 0.9,
-                   safecopy >= 0.6,
-                   uuid > 1.2,
-                   cereal > 0.3, 
-                   either >= 3.1 
+                   transformers >= 0.3,
+                   free >= 4.0
 
   Other-Modules:   
   exposed-modules:
diff --git a/src/Control/Monad/Trans/Crtn.hs b/src/Control/Monad/Trans/Crtn.hs
--- a/src/Control/Monad/Trans/Crtn.hs
+++ b/src/Control/Monad/Trans/Crtn.hs
@@ -4,7 +4,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      : Control.Monad.Trans.Crtn
--- Copyright   : (c) 2012 Ian-Woo Kim
+-- Copyright   : (c) 2012-2016 Ian-Woo Kim
 --
 -- License     : BSD3
 -- Maintainer  : Ian-Woo Kim <ianwookim@gmail.com>
@@ -17,19 +17,9 @@
 
 module Control.Monad.Trans.Crtn where 
 
--- import Control.Monad.Error
 import Control.Monad.Reader 
 import Control.Monad.State 
 import Control.Monad.Trans.Free
-
-
-----------------------------
--- added instance of FreeT monad
-----------------------------
-
-instance (Monad m, MonadState st m, Functor f) => MonadState st (FreeT f m) where 
-  get = lift get
-  put = lift . put
 
 ---------------------------
 -- general generator