7 hidden Blender hacks that will improve your workflow - CG Cookie
How to subdivide in Blender 2.8 & 2.79 | Tutorial - shortcuts - YouTube
How to subdivide a shape in Blender - Quora
I was proud of my topology until I tried subdividing... I need the empty quad face to remain sharp, help please! [More info in comments] : r/blenderhelp
How to ADD MORE VERTICES to a 3D MODEL in Blender - Model subdivision - YouTube