Again, no, we don't have the reference. As to why? Well, if you really wan't to get down in a hurry. Keep in mind most turboprop pilots develop a deep instinctive connection between "slow" and "beta/reverse." Every landing, every turn, every stop while taxiing includes the use of the prop. After a few thousand hours it get's pretty hardwired. Once when floating slightly too far down a wet runway I found myself edging into ground fine without conscious thought. Everything worked out, but my body did one thing while my brain knew perfectly well it was a bad idea. Beta at altitude is probably a pre-meditated affair, but you know what happens if we get away with it once...