1. A. Altman and S. Kleiman, Introduction to Grothendieck duality theory, Lecture Notes in Mathematics, vol. 276, Springer-Verlag, New York, 1970.
2. M. Auslander and D.A. Buchsbaum, On ramification theory in Noetherian rings, Amer. J. Math. 81(1959), 749–765.
3. H. Bass, Differential Structure of Etale Extensions of Polynomial Algebras, Commutative Algebra (M. Hochster, C. Huneke, and J.D. Sally, eds.), Springer-Verlag, New York, 1989, Proceedings of a Microprogram Hold, June 15–July 2, 1987.
4. H. Bass, E. Connell, and D. Wright, The Jacobian Conjecture: Reduction of Degreeand Formal Expansion of the Inverse, Bulletin of the American Mathematical Society 7(1982), 287–330.
5. N. Bourbaki, Algebre, Hermann, Paris, ch. 4.