1. Patterson IR. Growing older: Tourism and leisure behaviour of older adults. Cabi, Australia; 2006.
2. Lohmann M, Aderhold P. Die RA-Trendstudie - Entwicklung der touristischen Nachfrage der Deutschen (Holiday travel trends 2020 - the RA trend survey - development of tourist demand among Germans). FUR, Urlaubsreisetrends 2020 Kiel, Germany; 2009.
3. Leeson GW. Environment, Health and Ageing. In Environmental Gerontology in Europe and Latin America. International Perspectives on Aging. 2016;13:93‒104
4. Royal Society. People and the planet. The Royal Society Science Policy Centre. London; 2012.
5. Biographical Research Methods and Their Use in the Study of Senior Tourism;Huber;International Journal of Tourism Research,2017