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• Validation:我々は正しいプロダクトをつくっているだろうか? (Are we building the right product?) Wikipedia contributors, "Software veri¸cation and validation," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/ index.php?title=Software_veri¸cation_and_validation&oldid=857883943 (accessed October 11, 2018).