ASHWORTH, A. (1996). Pre-contract Studies Development Economics, Tendering And Estimating Allan Ashworth. Addison-Wesley.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रASHWORTH, A. Pre-contract Studies Development Economics, Tendering And Estimating Allan Ashworth. Addison-Wesley, 1996.
एमएलए (8वां संस्करण) प्रशस्ति पत्रASHWORTH, A. Pre-contract Studies Development Economics, Tendering And Estimating Allan Ashworth. Addison-Wesley, 1996.
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