Path Tracing

Texture Sampling and Antialiasing

Ray Differentials

ray differentials -> mipmap Level
"10.1 Texture Sampling and Antialiasing" of "PBR Book V4"
"10.1 Sampling and Antialiasing" of "PBR Book V3"

Specular Antialiasing

Toksvig
normal variance
the NDF of the average normal and the average roughness (separately) is NOT the average NDF
NormalCurvatureToRoughness of "Unreal Engine"
TextureNormalVariance of "Unity3D"
"7.8.1 Mipmapping BRDF and Normal Maps" of "Real-Time Rendering Third Edition"
"9.13.1 Filtering Normals and Normal Distributions" of "Real-Time Rendering Fourth Edition"