1. Humboldt, A. (1996). VON, Ansichten der Natur, Tübingen: Cotta’schen Buchhandlung, 1808, Tr It, Quadri Della Natura, La Nuova Italia.
2. Die Siedlungsräume Mitteleuropas in frühgeschichtlicher Zeit;Forschungen zur Deutschen Landeskunde,1908
3. Sauer, C. (1925). The Morphology of Landscape, University of California.
4. Agnew, J., Livingstone, D.N., and Rogers, A. (1996). Human Geography. An Essential Anthology, Blackwell.
5. UNESCO (1992). Convention Concerning the Protection of the Word Cultural and Natural Heritage, UNESCO. WHC-92/CONF.002/12 14 December 1992 Original: English/French, Santa Fe, USA.