diff --git a/Test/Utility.hs b/Test/Utility.hs
--- a/Test/Utility.hs
+++ b/Test/Utility.hs
@@ -19,10 +19,8 @@
 
 instance Arbitrary Char where
    arbitrary = liftM (chr . (32+) . flip mod 96) arbitrary
-   coarbitrary = undefined
 
 instance Arbitrary a => Arbitrary (Maybe a) where
    arbitrary =
       arbitrary >>=
          \b -> if b then fmap Just arbitrary else return Nothing
-   coarbitrary = undefined
diff --git a/non-negative.cabal b/non-negative.cabal
--- a/non-negative.cabal
+++ b/non-negative.cabal
@@ -1,5 +1,5 @@
 Name:             non-negative
-Version:          0.1.1
+Version:          0.1.1.1
 License:          GPL
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
@@ -21,7 +21,7 @@
   description: Choose the new smaller, split-up base package.
 
 Source-Repository this
-  Tag:         0.1.1
+  Tag:         0.1.1.1
   Type:        darcs
   Location:    http://code.haskell.org/~thielema/non-negative/
 
diff --git a/src/Numeric/NonNegative/Class.hs b/src/Numeric/NonNegative/Class.hs
--- a/src/Numeric/NonNegative/Class.hs
+++ b/src/Numeric/NonNegative/Class.hs
@@ -6,10 +6,10 @@
 Portability :  Haskell 98
 
 A type class for non-negative numbers.
-Prominent instances are 'Numeric.NonNegative.Wrapper.T',
-peano numbers and types from "Data.Word".
-However, there is Monoid class for Word types.
-Maybe Word is not a candidate, since it has wrap-around semantics.
+Prominent instances are 'Numeric.NonNegative.Wrapper.T' and peano numbers.
+Types from "Data.Word" would also be candidates.
+However, there is no 'Monoid' instance for 'Word' types
+and they have wrap-around semantics.
 This class cannot do any checks,
 but it let you show to the user what arguments your function expects.
 Thus you must define class instances with care.