Sommerville, I., & Sawyer, P. (1977). Requirements engineering: A good practice guide. Wiley.
Chicago-viite (17. p.)Sommerville, Ian, ja Pete Sawyer. Requirements Engineering: A Good Practice Guide. Chichester, Eng. ; New York ; New Delhi: Wiley, 1977.
MLA-viite (8. p.)Sommerville, Ian, ja Pete Sawyer. Requirements Engineering: A Good Practice Guide. Wiley, 1977.
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