Philippines. National Economic Development Authority. (1975). Development in Region I: An annotated bibliography. National Economic Development Authority.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रPhilippines. National Economic Development Authority. Development in Region I: An Annotated Bibliography. [San Fernando, La Union]: National Economic Development Authority, 1975.
एमएलए (9वां संस्करण) प्रशस्ति पत्रPhilippines. National Economic Development Authority. Development in Region I: An Annotated Bibliography. National Economic Development Authority, 1975.
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