A couple of nice reads; A heavier read would be Dao of T'ai Ji Quan by Jou Tsung Hwa. A lighter but exceptional read for any martial artist would be Martial Mechanics by Phillip Star. He dedicates an entire chapter to reverse breathing.
Yeah the reverse breath was one of little gems that were lost when Japanese culture aquired Chinese culture. It's sort of like we can say weight underside but after 45 minutes of Yi Chuan post standing, we have an innate understanding of weight underside.
But I agree that breathing is the icing, not the cake.
Oh but what yummy icing it is when you know what you're doing