Starch INRA Hooper (Firm) & United States Travel Service. Research and Analysis Division. Belgium: A study of the international travel market. The Division, c1978.
Čikaški stil citiranja (17. izdanje)Starch INRA Hooper (Firm) i United States Travel Service. Research and Analysis Division. Belgium: A Study of the International Travel Market. [Washington: The Division, c1978.
MLA način citiranja (9. izdanje)Starch INRA Hooper (Firm) i United States Travel Service. Research and Analysis Division. Belgium: A Study of the International Travel Market. The Division, c1978.
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