diff --git a/CC-delcont-ref-tf.cabal b/CC-delcont-ref-tf.cabal
--- a/CC-delcont-ref-tf.cabal
+++ b/CC-delcont-ref-tf.cabal
@@ -1,5 +1,5 @@
 name:               CC-delcont-ref-tf
-version:            0.1.0.0
+version:            0.1.0.1
 author:             Oleg Kiselyov
 maintainer:         shelarcy <shelarcy@gmail.com>
 license:            BSD3
@@ -34,7 +34,7 @@
    Bench_nondet.hs
 
 library
- build-depends:      base >= 3 && < 5, mtl, ref-tf
+ build-depends:      base >= 3 && < 5, transformers >= 0.2, ref-tf
  exposed-modules:
     Control.Monad.CC.CCRef
  other-modules:
diff --git a/Control/Monad/CC/CCRef.hs b/Control/Monad/CC/CCRef.hs
--- a/Control/Monad/CC/CCRef.hs
+++ b/Control/Monad/CC/CCRef.hs
@@ -52,7 +52,8 @@
 
 
 import Control.Monad (liftM2)
-import Control.Monad.Trans
+import Control.Monad.IO.Class (MonadIO(..))
+import Control.Monad.Trans.Class (MonadTrans(..))
 import Control.Monad.Ref		-- Generic references
 
 import Control.Monad.ST			-- For tests only