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2. Crosby, P.B.: Quality is Free. McGraw-Hill Inc. (1979)
3. Juran, J.M.: Juran on Quality by Design. The Free Press, Division of Macmillan Inc. (1992)
4. Juran, J.M.: Quality Control Handbook, 3rd edn. McGraw-Hill Inc. (1974)
5. UK Sales and Supply of Goods Act (1994)