diff --git a/README.md b/README.md
index e629ca0..8765675 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ DampedDriven.py:
 	Driven-damped oscillators.  Options are: driven-damped pendulum and driven-damped double well potential.  Plots a two-dimensional Poincaré section.
 
 DoublePendulum.py: 
-	Double pendulum.
+	Double pendulum.  (See: https://galileo-unbound.blog/2020/10/18/the-ups-and-downs-of-the-compound-double-pendulum/)
 
 Duffing.py: 
 	Duffing oscillator.