I have recently come across the following book about harry Ferguson and the development of the Ferguson System. It is a most xcellent and extremely well researched read.
The book is: "Ferguson. Evolution of the System 1916-1946 by Bill Martin"
All enquiries to billmartin.thefergusonsystem@gmail.com
It is categorically the best book ever written about the Ferguson System and will not disappoint.
Good reading
John