8Higgins I,Welsh K, Uh W, et al .Influence of arsenic exposure and smoking on lung cancer among smelter workers: A pilot study[J]. Am J lnd Med , 1981,2:33.
9Lu FJ.Blackfoot disease: arsen or humic acid? [J]. Lancet ,1990,336:115.
10Hericko A. Blankfoot disease[J]. Environmental Health Perspectives,1994,102(2) : 157.