Crew, M. A. (1991). Competition and innovation in postal services. Kluwer Academic.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रCrew, Michael A. Competition and Innovation in Postal Services. Boston: Kluwer Academic, 1991.
एमएलए (9वां संस्करण) प्रशस्ति पत्रCrew, Michael A. Competition and Innovation in Postal Services. Kluwer Academic, 1991.
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