The Art of Alberto Lolli* from the book ”Struttura Uomo” "Gottfried Bammes “Die gestalt des menchen” или “Образ человека.”"
Material and texture study by BiwerVincent on deviantART
pixiv Spotlight - Tutorials about creating realistic and bumpy textures!
Material study by katorius on DeviantArt
Material (texture) practice + bonus 
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