minor README change

README.md

@@ -7,7 +7,7 @@ Fast and accurate clustering through imputation and dimensionality reduction for
 
 Most existing dimensionality reduction and clustering packages for single cell RNA-Seq (scRNA-Seq) data deal with dropouts by heavy modelling and computational machinery. Here we introduce *CIDR* (Clustering through Imputation and Dimensionality Reduction), an ultrafast algorithm which uses a novel yet very simple ‘implicit imputation’ approach to alleviate the impact of dropouts in scRNA-Seq data in a principled manner.
 
-For more details about *CIDR* refer to the [unpublished preprint](http://biorxiv.org/content/early/2016/08/10/068775) on BioRxiv.
+For more details about *CIDR* refer to the [preprint](http://biorxiv.org/content/early/2016/08/10/068775) on BioRxiv.
 
 Getting Started
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