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शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रVillanueva, Raymund, Leon Dulce, और Rosario Bella Guzman. Rio+20: United Nations Conference on Sustainable Development. Quezon City: DZUP, 2012.
एमएलए (9वां संस्करण) प्रशस्ति पत्रVillanueva, Raymund, et al. Rio+20: United Nations Conference on Sustainable Development. DZUP, 2012.
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