Não informado. (1969). Airline management and marketing including american aviation. Ziff-Davis Aviation Division.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Airline Management and Marketing Including American Aviation. Washington: Ziff-Davis Aviation Division, 1969.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Airline Management and Marketing Including American Aviation. Ziff-Davis Aviation Division, 1969.
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