Johansson, Niklas, and Anton Löfgren. Designing for Extensibility: An Action Research Study of Maximizing Extensibility by Means of Design Principles. N.p.: n.p., n.d. University of Gothenburg Department of Applied Information Technology, 29 May 2009. Web. 26 Apr. 2014. <https://gupea.ub.gu.se/bitstream/2077/20561/1/gupea_2077_20561_1.pdf （頁面存檔備份，存於網際網路檔案館）>.
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