http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod
日本語での紹介
http://qiita.com/kenjihiranabe/items/9eddc70e279861992274
http://www2.ocn.ne.jp/~yamagu/object/OCP-J.pdf
http://queens.db.toronto.edu/~papaggel/courses/csc309/docs/lectures/web-architectures.pdf