diff --git a/Data/Type/Natural.hs b/Data/Type/Natural.hs
--- a/Data/Type/Natural.hs
+++ b/Data/Type/Natural.hs
@@ -9,7 +9,7 @@
                      -- | Peano natural numbers. It will be promoted to the type-level natural number.
                      Nat(..),
                      -- | Singleton type for 'Nat'.
-                     SNat
+                     SNat, Sing (SZ, SS)
                     -- ** Smart constructors
                     , sZ, sS
                     -- ** Arithmetic functions and thir singletons.
diff --git a/type-natural.cabal b/type-natural.cabal
--- a/type-natural.cabal
+++ b/type-natural.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                type-natural
-version:             0.0.1.0
+version:             0.0.1.1
 synopsis:            Type-level natural and proofs of their properties.
 description:         Type-level natural numbers and proofs of their properties.
 homepage:            https://github.com/konn/type-natural
@@ -22,6 +22,6 @@
 library
   exposed-modules:     Data.Type.Natural
   -- other-modules:       
-  build-depends:       base ==4.6.*
-               ,       singletons ==0.8.*
-               ,       equational-reasoning ==0.0.*
+  build-depends:       base                     ==4.6.*
+               ,       singletons               ==0.8.*
+               ,       equational-reasoning     == 0.0.*