7 Ways to Get Rid of Fireflies Once and For All — Blender Guru
MISEmissive
Reducing Noise — Blender Manual
ephtracy on Twitter: "...multiple importance sampling (MIS) for the light interaction between GGX surfaces with different roughness and lights with different area (2000 spp) https://t.co/r5sBPJoyV5" / Twitter
BRDF Blending in Path Tracing with Multiple Importance Sampling
GAPT Series - 9] Sampling Algorithms (Cont.) - Daqi's Blog
Tip: Noise reduction in Blender Cycles using Multiple Importance Sample & Map Resolution setting - YouTube