A bit about Canon photography

I was looking for articles about the mineral fluorite, from which the lenses are made.
Got some pretty interesting PDFs on the official Canon website.

EF lens concept
Canon Achievements
EF Lens World Fixed Focus Lenses
Lens World EF Zoom Lens
EF Lens World EF-S Lens
EF Lens Accessories
Interchangeable Lenses Overview
Photography Technique
EF lens technology
Optical terminology
EF Lens Specifications