Agile Principles, Patterns, and Practices in C#

[Liskov88] "Data Abstraction and Hierarchy," Barbara Liskov, SIGPLAN Notices, 23(5) (May 1988).

[Meyer97] Bertrand Meyer, Object-Oriented Software Construction, 2d. ed., Prentice Hall, 1997.

[Wirfs-Brock90] Rebecca Wirfs-Brock et al. , Designing Object-Oriented Software, Prentice Hall, 1990.