1. R. Berger, Differentialmoduln eindimensionaler lokaler Ringe. Math. Z.81, 326?354 (1963).
2. N.Bourbaki, Alg�bre commutative, Chap. 3 et 4. Paris 1967.
3. N.Bourbaki, Alg�bre commutative, Chap. 7. Paris 1965.
4. A.Grothendieck et J.Dieudonn�, �l�ments de Geom�trie alg�brique, Chap. 4 (Quatri�me Partie). Publ. math. Inst. Htes. Et. Scient.32 (1967).
5. D.Mumford, Lectures on Curves on an Algebraic Surface. Princeton 1966.