Pekka Abrahamsson Michele Marchesi Giancarlo Succi Extreme Programming and Agile Processes in Software Engineering, 7th International Conference, XP 2006, Oulu, Finland, June 17-22, 2006, Proceedings 4044 2006 3-540-35094-2 XP Lecture Notes in Computer Science Springer db/conf/xpu/xp2006.html