diff --git a/Test/Numeric/NonNegative/Chunky.hs b/Test/Numeric/NonNegative/Chunky.hs
--- a/Test/Numeric/NonNegative/Chunky.hs
+++ b/Test/Numeric/NonNegative/Chunky.hs
@@ -8,7 +8,7 @@
 module Test.Numeric.NonNegative.Chunky (tests) where
 
 -- import Test.Utility
-import Test.QuickCheck (test, Property, (==>))
+import Test.QuickCheck (quickCheck, Property, (==>))
 
 import qualified Numeric.NonNegative.Chunky  as Chunky
 import qualified Numeric.NonNegative.Class   as NonNeg
@@ -161,56 +161,56 @@
 
 
 
-type Card = NonNegW.T Int
+type Card = NonNegW.Integer
 
 tests :: [(String, IO ())]
 tests =
    ("add",
-     test (add :: Chunky.T Card -> Chunky.T Card -> Bool)) :
+     quickCheck (add :: Chunky.T Card -> Chunky.T Card -> Bool)) :
    ("sub",
-     test (sub :: Chunky.T Card -> Chunky.T Card -> Bool)) :
+     quickCheck (sub :: Chunky.T Card -> Chunky.T Card -> Bool)) :
    ("mul",
-     test (mul :: Chunky.T Card -> Chunky.T Card -> Bool)) :
+     quickCheck (mul :: Chunky.T Card -> Chunky.T Card -> Bool)) :
    ("min",
-     test (min :: Chunky.T Card -> Chunky.T Card -> Bool)) :
+     quickCheck (min :: Chunky.T Card -> Chunky.T Card -> Bool)) :
    ("max",
-     test (max :: Chunky.T Card -> Chunky.T Card -> Bool)) :
+     quickCheck (max :: Chunky.T Card -> Chunky.T Card -> Bool)) :
    ("abs",
-     test (abs :: Chunky.T Card -> Bool)) :
+     quickCheck (abs :: Chunky.T Card -> Bool)) :
    ("signum",
-     test (signum :: Chunky.T Card -> Bool)) :
+     quickCheck (signum :: Chunky.T Card -> Bool)) :
    ("equal",
-     test (equal :: Chunky.T Card -> Chunky.T Card -> Bool)) :
+     quickCheck (equal :: Chunky.T Card -> Chunky.T Card -> Bool)) :
    ("compare",
-     test (compare :: Chunky.T Card -> Chunky.T Card -> Bool)) :
+     quickCheck (compare :: Chunky.T Card -> Chunky.T Card -> Bool)) :
 
    ("addInfiniteL",
-     test (addInfiniteL :: Card -> Card -> Chunky.T Card -> Bool)) :
+     quickCheck (addInfiniteL :: Card -> Card -> Chunky.T Card -> Bool)) :
    ("addInfiniteR",
-     test (addInfiniteR :: Card -> Card -> Chunky.T Card -> Bool)) :
+     quickCheck (addInfiniteR :: Card -> Card -> Chunky.T Card -> Bool)) :
    ("mulInfiniteL",
-     test (mulInfiniteL :: Card -> Card -> Chunky.T Card -> Property)) :
+     quickCheck (mulInfiniteL :: Card -> Card -> Chunky.T Card -> Property)) :
    ("mulInfiniteR",
-     test (mulInfiniteR :: Card -> Card -> Chunky.T Card -> Property)) :
+     quickCheck (mulInfiniteR :: Card -> Card -> Chunky.T Card -> Property)) :
    ("minRecursiveL",
-     test (minRecursiveL :: Chunky.T Card -> Chunky.T Card -> Property)) :
+     quickCheck (minRecursiveL :: Chunky.T Card -> Chunky.T Card -> Property)) :
    ("minRecursiveR",
-     test (minRecursiveR :: Chunky.T Card -> Chunky.T Card -> Property)) :
+     quickCheck (minRecursiveR :: Chunky.T Card -> Chunky.T Card -> Property)) :
    ("minInfiniteL",
-     test (minInfiniteL :: Card -> Chunky.T Card -> Bool)) :
+     quickCheck (minInfiniteL :: Card -> Chunky.T Card -> Bool)) :
    ("minInfiniteR",
-     test (minInfiniteR :: Card -> Chunky.T Card -> Bool)) :
+     quickCheck (minInfiniteR :: Card -> Chunky.T Card -> Bool)) :
    ("maxInfiniteL",
-     test (maxInfiniteL :: Card -> Card -> Chunky.T Card -> Bool)) :
+     quickCheck (maxInfiniteL :: Card -> Card -> Chunky.T Card -> Bool)) :
    ("maxInfiniteR",
-     test (maxInfiniteR :: Card -> Card -> Chunky.T Card -> Bool)) :
+     quickCheck (maxInfiniteR :: Card -> Card -> Chunky.T Card -> Bool)) :
    ("minInfiniteAssociative",
-     test (minInfiniteAssociative :: Card -> Card -> Chunky.T Card -> Bool)) :
+     quickCheck (minInfiniteAssociative :: Card -> Card -> Chunky.T Card -> Bool)) :
    ("maxInfiniteAssociative",
-     test (maxInfiniteAssociative :: Card -> Card -> Card -> Chunky.T Card -> Bool)) :
+     quickCheck (maxInfiniteAssociative :: Card -> Card -> Card -> Chunky.T Card -> Bool)) :
 
    ("compareInfiniteL",
-     test (compareInfiniteL :: Card -> Chunky.T Card -> Bool)) :
+     quickCheck (compareInfiniteL :: Card -> Chunky.T Card -> Bool)) :
    ("compareInfiniteR",
-     test (compareInfiniteR :: Card -> Chunky.T Card -> Bool)) :
+     quickCheck (compareInfiniteR :: Card -> Chunky.T Card -> Bool)) :
    []
diff --git a/non-negative.cabal b/non-negative.cabal
--- a/non-negative.cabal
+++ b/non-negative.cabal
@@ -1,10 +1,10 @@
 Name:             non-negative
-Version:          0.0.5
+Version:          0.0.5.1
 License:          GPL
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
 Maintainer:       Henning Thielemann <haskell@henning-thielemann.de>
-Homepage:         http://darcs.haskell.org/non-negative/
+Homepage:         http://code.haskell.org/~thielema/non-negative/
 Category:         Math
 Synopsis:         Non-negative numbers
 Description:
@@ -25,7 +25,7 @@
   default:     False
 
 Library
-  Build-Depends: QuickCheck >= 1.0 && <2
+  Build-Depends: QuickCheck >= 1.0 && <3
   If flag(splitBase)
     Build-Depends: base >= 2 && < 5
   Else
diff --git a/src/Numeric/NonNegative/ChunkyPrivate.hs b/src/Numeric/NonNegative/ChunkyPrivate.hs
--- a/src/Numeric/NonNegative/ChunkyPrivate.hs
+++ b/src/Numeric/NonNegative/ChunkyPrivate.hs
@@ -17,10 +17,11 @@
     fromChunksUnsafe, toChunksUnsafe, ) where
 
 import qualified Numeric.NonNegative.Class as NonNeg
+import Numeric.NonNegative.Class ((-|), )
 import Control.Monad (liftM, liftM2)
 
 import qualified Data.Monoid as Mn
-import Test.QuickCheck (Arbitrary(..))
+import Test.QuickCheck (Arbitrary(arbitrary))
 
 {- |
 A chunky non-negative number is a list of non-negative numbers.
@@ -95,8 +96,8 @@
 glue (x:xs) (y:ys) =
    let (z,(zs,rs,b)) =
            case compare x y of
-              LT -> (x, glue xs ((y-x):ys))
-              GT -> (y, glue ((x-y):xs) ys)
+              LT -> (x, glue xs ((y-|x):ys))
+              GT -> (y, glue ((x-|y):xs) ys)
               EQ -> (x, glue xs ys)
    in  (z:zs,rs,b)
 
@@ -146,7 +147,7 @@
    (Cons x) -| (Cons w) =
       let sub _ [] = []
           sub z (y:ys) =
-             if z<y then (y-z):ys else sub (z-y) ys
+             if z<y then (y-|z):ys else sub (z-|y) ys
       in  Cons (foldr sub x w)
 
 instance (NonNeg.C a) => Num (T a) where
@@ -168,7 +169,6 @@
 
 instance (NonNeg.C a, Arbitrary a) => Arbitrary (T a) where
    arbitrary = liftM Cons arbitrary
-   coarbitrary = undefined
 
 
 {- * Functions that may break invariants -}
diff --git a/src/Numeric/NonNegative/Wrapper.hs b/src/Numeric/NonNegative/Wrapper.hs
--- a/src/Numeric/NonNegative/Wrapper.hs
+++ b/src/Numeric/NonNegative/Wrapper.hs
@@ -16,7 +16,7 @@
 
 import qualified Numeric.NonNegative.Class as NonNeg
 
-import Test.QuickCheck (Arbitrary(..))
+import Test.QuickCheck (Arbitrary(arbitrary))
 import Numeric.NonNegative.Utility(mapPair, mapSnd)
 import Control.Monad (liftM)
 
@@ -174,7 +174,6 @@
 
 instance (Num a, Arbitrary a) => Arbitrary (T a) where
    arbitrary = liftM (Cons . abs) arbitrary
-   coarbitrary = undefined
 
 
 type Int      = T P.Int