diff --git a/README.md b/README.md
index 379a9f9..e233a9b 100644
--- a/README.md
+++ b/README.md
@@ -14,3 +14,5 @@ See [Haddock docs](https://hackage.haskell.org/package/number/docs/Data-Number.h
 Dual licensed under the MIT and GPL licenses:  
 http://www.opensource.org/licenses/mit-license.php  
 http://www.gnu.org/licenses/gpl.html
+
+[Data.Number.Peano](src/Data/Number/Peano.hs) is a slightly modified version of the package [numeric-peano](http://hackage.haskell.org/package/numericpeano)
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