diff --git a/docs/preparation.md b/docs/preparation.md
index bcc76f8..0915462 100644
--- a/docs/preparation.md
+++ b/docs/preparation.md
@@ -20,4 +20,4 @@ Optional tools
 
   * [scikit-learn](http://scikit-learn.org/) for Python 3, required for PCA analysis (helper script)
   * [seaborn](https://stanford.edu/~mwaskom/software/seaborn/) for Python 3, required for PCA analysis (helper script)
-  * [Aspera connect client](), required for the *get_sra_ip.py* (helper script)
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+  * [Aspera connect client](http://downloads.asperasoft.com/en/downloads/2), required for the *get_sra_ip.py* (helper script)
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