diff --git a/Machine Learning for Economics and Finance/README.md b/Machine Learning for Economics and Finance/README.md
index c174da7..532aedd 100644
--- a/Machine Learning for Economics and Finance/README.md
+++ b/Machine Learning for Economics and Finance/README.md
@@ -25,6 +25,15 @@ This project contains material to the university introduction course "Machine Le
- Deep Learnin
- Neural Networks
+
+## Main Reference (ISL):
+- James, G., D. Witten, T. Hastie, and R. Tibshirani (2013). An Introduction to Statistical Learning with Applications in Python (Book link).
+- The book as well as Python tutorials, datasets and practice exercises are available on the website.
+
+## More advanced (ESL):
+- T. Hastie, R. Tibshirani and J. Friedman. The Elements of Statistical Learning (Book link).
+
+