FACS
Facial Action Coding System (FACS) - A Visual Guidebook - iMotions
Discover the Facial Action Coding System (FACS) and learn about human facial expressions in this visual guidebook.
Bryn Farnsworth
https://www.kairos.com/blog/facial-action-coding-system
https://www.fxguide.com/fxfeatured/performance-driven-facial-animation/