1. Ashworth GJ, de Haan TZ (1985) The Tourist-Historic City: A Model and Initial Application in Norwich. U.K. Field Studies Series n. 8, Geographical Institute, University of Groningen.
2. Bateson G (1973) Steps to an Ecology of Mind, Granada, St. Albans.
3. Burtenshaw D, Bateman M, Ashworth G (1991) The European City, David Fulton Publishers, London.
4. Chang C, Milne TS, Fallon D, Pohlmann C (1996) Urban heritage tourism: The global-local nexus. Annals of Tourism Research n. 23 (2), pp. 284–305.
5. Conforti JM (1996) Ghettos as tourism attractions. Annals of Tourism Research n. 23 (4), pp. 830–842.