1. Adams, M. (2006). Nautical wine tourism: A strategic plan to create a nautical wine trail in the Finger Lakes wine tourism region of New York State. In J. Carlsen & S. Charters (Eds.), Global wine tourism: Research management and marketing (pp. 227–241). Oxon: CAB International.
2. All Ways Cruises. (2015). Le Douro au départ de Porto avec Salamanque. Retrieved 15 December, 2014, from
http://www.all-ways.be/pdf/1758/1758_fr.pdf
3. Ama Waterways. (2015). Wine Cruises Through Europe: 2015 & 2016. Retrieved 15 December, 2014, from
http://www.amawaterways.com/brochures/2015-2016wine/wine-2015-2016.pdf
4. Andresen, T., & Rebelo, J. (2013). Assessment of the state of conservation of the property Alto Douro wine region – Evolutive and living cultural landscape – Assessment report. Porto: CCDRN/EMD & CIBIO UP/UTAD.
5. Baloglu, S. (1997). The relationship between destination images and sociodemographic and trip characteristics of international travellers. Journal of Vacations Marketing, 3(3), 221–233.