UNESCO. (1999). Adult learning and the challenges of the 21st century. UNESCO.
शिकागो स्टाइल उद्धरणUNESCO. Adult Learning and the Challenges of the 21st Century. Germany: UNESCO, 1999.
एमएलए उद्धरणUNESCO. Adult Learning and the Challenges of the 21st Century. UNESCO, 1999.
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