1. L. O. Chung, A. Kovacs, and J. Luh, Algebraic derivations, preprint.
2. Nilpotent derivations in an ideal;Chung,1984
3. Differential identities of prime rings;Kharchenko;Algebra and Logic,1978
4. Generalized identities with automorphisms;Kharchenko;Algebra and Logic,1975
5. Nilpotent derivations;Kovacs;Technion preprint series, Mt-453,1979