Venners, Bill (6. 6. 2005). „Leading-Edge Java: Design Principles from Design Patterns: Program to an interface, not an implementation - A Conversation with Erich Gamma, Part III”. http://www.artima.com/index.jsp: artima developer. Приступљено 3. 8. 2011. „Once you depend on interfaces only, you're decoupled from the implementation. That means the implementation can vary, and that is a healthy dependency relationship. For example, for testing purposes you can replace a heavy database implementation with a lighter-weight mock implementation. Fortunately, with today's refactoring support you no longer have to come up with an interface up front. You can distill an interface from a concrete class once you have the full insights into a problem. The intended interface is just one 'extract interface' refactoring away. ...”
