Add link to Alek's post of the same graph theory proof

content/posts/extremal-graph-theory.md

@@ -36,3 +36,5 @@ Thus, we get our bound.
 $$\frac{N^2}{4} \geq M$$
 
 This bound is tight with our earlier result, so we can't do better than a complete bipartite graph with two even halves. And that's it!
+
+Alek wrote up the same [proof of this theorem on his blog](https://awestover.github.io/skyspace/posts/graphtheory/01-14-24.html) as well.