Project Maiko: Understanding Cycles Toon Shaders — aVersion of Reality
Cycles material node set-up for diffuse, specular, reflection/refraction, normal and illumination/emission map - Blender Stack Exchange
Physics and Creating Plausible Materials.
Specular vs Metalness Workflows for PBR Shading in Blender - YouTube
Blender tutorial: materials
texturing - How to apply normal-, gloss-, occlusion-, specularity- and displacement map on one cycles material? - Blender Stack Exchange
Specular Shaders — Blender Manual
Diffuse Shaders — Blender Manual
computer vision - How to render different maps (diffuse, depth, specular, shaded) of a 3d model from different camera angles, in Blender? - Stack Overflow
Specular Shaders - Dark Exporter Documentation, Unofficial Dromed Tutorial
Blender 3D tip — Realistic Specular value in Principled shader