Thank you for posting that. Well done and very readable.

For the books. These are where I have found many of them.
Ebay
Alibris.com - is where I get many of my out of print/hard to find books. Often at very decent prices
Google the title and see what pops up

I have a mint Standard Textbook of Barbering 3rd edition from Alibris and a minty Practical and Scientific Barbering fourth ed. 1959

Very informative. I learned how to hold a brush from a post that someone took from a barber book. 2 fingers supporting the bristles.