diff --git a/README.md b/README.md
index 439f12554fbdb8271a587092af1e27b89622f6c2..42e1df841371f11c0ed1a8a70144b5deb57b0b3f 100644
--- a/README.md
+++ b/README.md
@@ -39,3 +39,7 @@ If you experience problems with [Tensorflow](https://tensorflow.org), such as in
 # License
 
 Released under the GPLv3 License (see [LICENSE](https://github.com/mooch443/trex/blob/master/LICENSE)).
+
+# Reference
+
+A preprint is available at https://preprint.trex.run/.