Martin Lippert Petra Becker-Pechau Holger Breitling Jörn Koch Andreas Kornstädt Stefan Roock Axel Schmolitzky Henning Wolf Heinz Züllighoven Developing Complex Projects Using XP with Extensions. 67-73 2003 36 IEEE Computer 6 http://doi.ieeecomputersociety.org/10.1109/MC.2003.1204377 db/journals/computer/computer36.html#LippertBBKKRSWZ03