開放/閉鎖原則
Meyer, Bertrand (1988). Object-Oriented Software Construction. Prentice Hall. ISBN 978-0136290315
Martin, Robert C. (January 1996). “The Open-Closed Principle” (PDF). C++ Report. http://www.objectmentor.com/resources/articles/ocp.pdf. 和訳 The Open-Closed Principle(開放-閉鎖原則)