Is it better to have models that have double faces or is it better to have a two-sided material instead? - Pipeline & Plugins - Epic Developer Community Forums
Two-sided shading (NOT backfacing) - for animation - CG Cookie
Double Sided Materials in Blender — Blender Daily
How to Create a Double-Sided Material in Blender - Lesterbanks
Double Sided Textures In Blender – polygonartist.
Blender Sushi: RENDER / Wired & Double-Sided Useful Material Tricks