diff --git a/google-isbn.cabal b/google-isbn.cabal
--- a/google-isbn.cabal
+++ b/google-isbn.cabal
@@ -2,10 +2,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 0202f3a2dea5a9717b5afad325fb888ee6b8504f6c4c528871c6ccbebc5e5817
+-- hash: f555cf18c6f53f5e6b0d34c4a34655d7431c535b1f7421adf7ccd6d8dc2fb2b1
 
 name:           google-isbn
-version:        0.2
+version:        0.3
 description:    Basic utility to search an ISBN using the Google Books webservice
 category:       Text, Web
 homepage:       https://github.com/apeyroux/google-isbn#readme
diff --git a/src/Google/ISBN.hs b/src/Google/ISBN.hs
--- a/src/Google/ISBN.hs
+++ b/src/Google/ISBN.hs
@@ -11,8 +11,8 @@
 
 module Google.ISBN (
   ISBN
-  , GoogleISBN
-  , Book
+  , GoogleISBN (..)
+  , Book (..)
   , googleISBN
   ) where