Schonberger, R. J. (1991). Operations management: Improving customer service (4th.). Irwin.
Chicago-viite (17. p.)Schonberger, Richard J. Operations Management: Improving Customer Service. 4th. Homewood: Irwin, 1991.
MLA-viite (9. p.)Schonberger, Richard J. Operations Management: Improving Customer Service. 4th. Irwin, 1991.
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