Stats on back pain
https://www.cdc.gov/acute-pain/low-back-pain/index.html
https://www.iaff.org/back-injuries/
Healing Back Pain Book
https://www.amazon.com/dp/B00FOTRI4S/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1
Science of Yoga Book
https://www.amazon.com/dp/B08WCHRJJG/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1