Urhausen, J. (2008). Tourism in Europe: Does age matter? Statistics in focus: Industry, trade and services.
Chicago-Zitierstil (17. Ausg.)Urhausen, Julia. "Tourism in Europe: Does Age Matter?" Statistics in Focus: Industry, Trade and Services 2008.
MLA-Zitierstil (8. Ausg.)Urhausen, Julia. "Tourism in Europe: Does Age Matter?" Statistics in Focus: Industry, Trade and Services, 2008.
警告：這些引文格式不一定是100％准確.