Piano Servicing, Tuning, and Rebuilding: For the Professional, the Student, and the Hobbyist by Arthur Reblitz is the standard text I recommend for my Basic Piano Tuning and Basic Piano Repair courses.
It is an excellent resource for repair and regulation, although I find it a bit weak on tuning. (That’s why I wrote my Basic Piano Tuning Course Manual)
However, the upright regulation steps listed in Reblitz, have room for improvement.
Some steps refer to adjustments that usually don’t need to be done if they’ve been done already, like positioning the let off rail. Some steps refer to adjustments that could make things worse, like changing the back checks. (It is not as critical, and if they are all in a straight line, adjustment may leave them not as straight.)
Also, instructions are given to set all the blow distance at once. Same with key dip, and let off. I was taught to set a few samples first, in order to confirm the ideal blow distance, let off, and key dip that produces appropriate aftertouch for that piano. (I call blow distance, let off and key dip, the Regulation Triangle and I’m writing a book on how to regulate a piano using this method. See Regulation Triangle Method for Easily Understanding Upright and Grand Regulation)
If you are interested in reading my full modifications for the upright regulation steps listed the Reblitz book, just enter your email HERE.