Jun Tomiyama, Masamichi Takesaki, Applications of fibre bundles to the certain class of -algebras, Tohoku Math. J. (2) 13:3 (1961) 498-522 eucliddoi
The comparison of the Artin’s theorem on characterization of Azumaya algebras and Tomiyama-Takesaki’s theorem on -homogeneous -algebras is in chapter 9 of
Edward Formanek, Noncommutative invariant theory, in: Group actions on rings (Brunswick, Maine, 1984), 87–119, Contemp. Math. 43, Amer. Math. Soc. 1985 doi