three.js - Diffuse BRDF
Disney: "Physically-Based Rendering At Disney"
Renormalized Disney: "Moving Frostbite to Physically Based Rendering 3.0"
Improved Oren-Nayar, Fast Improved Oren-Nayar: "A tiny improvement of Oren-Nayar reflectance model"
Normalized Oren-Nayar, GGX Oren-Nayar: "Designing Reflectance Models for New Consoles"
GGX Approximation: "PBR Diffuse Lighting for GGX+Smith Microsurfaces"