diff --git a/js/diagrams.js b/js/diagrams.js
index 443a4da..b597a9e 100644
--- a/js/diagrams.js
+++ b/js/diagrams.js
@@ -1,6 +1,7 @@
 "use strict";
 
 // https://bl.ocks.org/mbostock/3884955
+// https://bl.ocks.org/mbostock/34f08d5e11952a80609169b7917d4172
 function createLineGraph(containerId, raceData){
 
   // Rough input validation