I read a ton. I read a ton of sales stuff. I read a ton of sales management stuff.
No one has it nailed more than Keith Rosen. I, literally, owe this guy a consulting fee for everything he has helped me with. I changed my entire management style after reading his book "Coach Salespeople into Sales Champions."
The questions he has are masterful and I use them every week during multiple coaching sessions.
I know the article below is 4 years old, but it is timeless content. If you manage people, read it now!
Are You Selling by the Numbers or Selling Blindfolded? by Keith Rosen