7Allan J A. Overall perspectives on countries and regions[A]. In: Rogers P, Lydon, P. Water in the Arab world: perspectives and prognoses [C]. Harvard university press, Cambridge, Massachusetts, 1994.65- 100.
8Hoekstra A Y. Virtual water trade: an introduction[A]. In: Hoekstra A Y. Virtual Water Trade: Proceedings of the International Expert Meeting on Virtual Water Trade[C]. Value of Water Research Report Series No12. IHE DELFT, 2003.13 -23.
9Wackernagel M, Onisto L, Linares A C, et al. Ecological footprints of nations: How much nature do they use? - How much nature do they have? [M]. Centre for Sustainability Studies, Universidad Anahuac de Xalapa, Mexico, 1997.
10Chapagain A K, Hoekstra A Y. Virtual water trade: A quantification of virtual water flows between nations in relation to international trade of livestock and livestock products[A]. In: Hoekstra A Y edited. Virtual Water Trade: Proceedings of the International Expert Meeting on Virtual Water Trade [C]. Value of Water Research Report Series No12. IHE DELFT, 2003.