International Union of Official Travel Organisations. (1971). Methodology for annual and medium-term forecasts. International Union of Official Travel Organisations.
Chicagoスタイル(17版)引用形式International Union of Official Travel Organisations. Methodology for Annual and Medium-term Forecasts. Geneva: International Union of Official Travel Organisations, 1971.
MLA(9版)引用形式International Union of Official Travel Organisations. Methodology for Annual and Medium-term Forecasts. International Union of Official Travel Organisations, 1971.
警告: この引用は必ずしも正確ではありません.