APA (7e ed.) Bronvermelding

International Union of Official Travel Organisations. (1971). Methodology for annual and medium-term forecasts. International Union of Official Travel Organisations.

Chicago (17e ed.) Bronvermelding

International Union of Official Travel Organisations. Methodology for Annual and Medium-term Forecasts. Geneva: International Union of Official Travel Organisations, 1971.

MLA (9e ed.) Bronvermelding

International Union of Official Travel Organisations. Methodology for Annual and Medium-term Forecasts. International Union of Official Travel Organisations, 1971.