Sparling, R. C. (1968). 1967 Annual financial analysis of a group of petroleum companies. New York: The Chase Manhattan Bank.
Παραπομπή Chicago StyleSparling, Richard C. 1967 Annual Financial Analysis of a Group of Petroleum Companies. New York: The Chase Manhattan Bank, 1968.
Παραπομπή MLASparling, Richard C. 1967 Annual Financial Analysis of a Group of Petroleum Companies. New York: The Chase Manhattan Bank, 1968.
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