REFERENCES
- Bell , A. D. 2000 . Comodule Algebras and Galois Extensions Relative to Polynomial Algebras, Free Algebras, and Enveloping Algebras . Comm. Algebra , 28 : 337 – 362 .
- Chase , S. U. , Harrison , D. K. and Rosenberg , A. Galois Theory and Cohomology of Commutative Rings , AMS Memoirs No. 52 . 1965
- Doi , Y. and Takeuchi , M. 1986 . Cleft Comodule Algebras for a Bialgebra . Comm. Alg. , 14 : 801 – 818 .
- Kreimer , H. F. and Takeuchi , M. 1981 . Hopf Algebras and Galois Extensions of an Algebra . Indiana Univ. Math. J. , 30 : 675 – 692 .
- Montgomery , S. 1993 . Hopf Algebras and Their Actions on Rings AMS Providence R.I. .
- Schneider , H. J. 1990 . Principal Homogeneous Spaces for Arbitrary Hopf Algebras . Israel J. Math. , 72 : 167 – 195 .
- Ulbrich , K. H. 1981 . Vollgraduierte Algebren . Abh. Math. Sem. Univ. Hamburg , 51 : 136 – 148 .