1. Maximal orders;Auslander;Trans. Amer. Math. Soc.,1960
2. Elements of mathematics, “Algebra,”;Bourbaki,1974
3. Elements of mathematics, “Commutative Algebra,”;Bourbaki,1972
4. Galois theory and Galois cohomology of commutative rings;Chase;Mem. Amer. Math. Soc.,1965
5. Hopf Algebras and Galois Theory;Chase,1969