7Hawksworth D L, Francis Rose. Lichens as pollution monitors[M]. London: Edward Arnold, 1975, 1-8.
8Ritchie J C, Mchenry J R. Application of radioactive fallout ^137 Cs for measuring soil erosion and sediment accumulation rates and patterns: A review[J]. Journal of Environmental Quality, 1990,(19) :215 - 233.
9Walling D E, He Q. Improved models for estimating soil erosion rates from Cesium- 137 measurement [ J]. Journal of Environmental Quality, 1999, (28) :611 - 622.
10Baeza A, Miro C, Paniagua J M, et al. Natural and Artificial Radioactivity Levels in Livingston Isoland (Antarctic Regions)[J]. Environ. Contamin. & Taxicol., 1994, (52):117-124.
