Hayes, S. P. (1966). Evaluating development projects: A manual for the use of field workers (2nd ed., rev.). Unesco.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रHayes, Samuel Perkins. Evaluating Development Projects: A Manual for the Use of Field Workers. 2nd ed., rev. [Paris]: Unesco, 1966.
एमएलए (9वां संस्करण) प्रशस्ति पत्रHayes, Samuel Perkins. Evaluating Development Projects: A Manual for the Use of Field Workers. 2nd ed., rev. Unesco, 1966.
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