Não informado. (1968). World meetings outside United States and Canada. Technical Meetings Information Service.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. World Meetings Outside United States and Canada. Newton Centre, Mass: Technical Meetings Information Service, 1968.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. World Meetings Outside United States and Canada. Technical Meetings Information Service, 1968.
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