ALIN STANCU ExtiA,k(M, N) ≃ M orDk−(A−mod)(M•, N•[i]) ExtiA′,k(M′, N′) ≃ M orDk−(A′−mod)(M′•, N′•[i])  S. I. Gelfand and Yu. I. Manin, “Methods of Homological Algebra”, Springer Verlag (1996).
 M. Gerstenhaber and S. D. Schack, “Algebraic Cohomology and Deformation Theory”, Deformation Theory of Algebras and Structures and Applications, Kluwer, Dordrecht (1988) 11-264.
 M. Gerstenhaber and S. D. Schack, “The Cohomology of Presheaves of Algebras: Presheaves over a Partially Ordered Set”, Trans. Amer. Math. Soc. 310 (1988) 135-165.
 S. MacLane, “Homology ”, Spinger-Verlag, Berlin, (1967).
 A. A. Stancu, “Hochschild Coheomology and Derived Categories”, SUNY at Buffalo Ph.D. thesis, (2006).
 A. A. Stancu, “On the Cohomology Comparison Theorem”, Journal of Homotopy and Related Structures, to appear.
E-mail address: stancu email@example.com