August Haas is a young trumpet player from Milwaukee who has been increasing in prominence in recent years. His doctoral dissertation is entitled "The Art of Trumpet Playing in the Upper Register". It does a nice job of rounding up information familiar to some of us and packaging it neatly in a single document. His sources are perceived by many to be legitimate and authoritative. Also, the information presented is not restricted to playing in the upper register.
Mr. Haas' dissertation is available here: http://scholarlyrepository.miami.edu..._dissertations. Note: this dissertation may have been posted here on TM before, but if so, I believe it has been a while ago.