7Kristiansson K, Malmqvist L. Evidence for no diffusive transport of Rn in the ground and a new physical model for the transport. [ J]. Geophysics, 1982,47 ( 10 ) : 1444.
8Clark J R, Meier A L, Riddle. Enzyme leaching of surficial geochemical samples for defecting hydromorphic trace-element anomalies associated with precious-metal mineralized bedrock buried beneath glacial overburden in no,hem Minnesota [ R ]. In : GOLD' 90,1990 : 189.
9Mann A W, Birrell R D, Gay L M, et al. Pretrial extractions and mobile metal ions[ C]//Camuti K S. Extended abstracts of the 17th IGES, 1995:31.
10Wang Xueqiu. Leaching of mobile forms of metals in overburden:development and applications [ J ]. J Geochem Explor, 1998,61 : 1.
