Add the "Demystifying multiple importance sampling" article

Author: bobeff

README.md

@@ -378,6 +378,8 @@ This is a list of links to different freely available learning resources about c
 
 * [A raycasting engine in 7 easy steps](https://austinhenley.com/blog/raycasting.html) by *Austin Z. Henley*
 
+* [Demystifying multiple importance sampling](https://lisyarus.github.io/blog/posts/multiple-importance-sampling.html) by *Nikita Lisitsa*
+
 * [Getting Started With DirectX Raytracing](https://renderingpixels.com/2022/07/getting-started-with-directx-raytracing) by *Seppe Dekeyser*
 
 * [How to build a BVH](https://jacco.ompf2.com/2022/04/13/how-to-build-a-bvh-part-1-basics) by *Jacco Bikker*