References
- Drozd , Y. A. and Roggenkamp , K. W. 1994 . Cohen Macaulay rings of global dimension two and Krull dimension two . Com. Algebra , 22 ( 9 ) : 3297 – 3329 .
- Lam , T. Y. 1978 . Serre's conjecture, Lecture Notes in Mathematics 635 , New York : Springer-Verlag, Berlin Heidelberg .