8Hnizdo E, Murray J, Klempman S. Lung cancer in relation to exposure to silica dust, silicosis and uranium production in South African gold mine. Occup Health Ind Med, 1997, 36(6): 280
9King A M. Health dust monitoring at Derlwyn opencast coal sit.J Aerosol Sci, 1997, 28(2): 336
10Fulekar M H. Occupational exposure to dust in quartz manufacturing industry. Ann Occup Hyg, 1999, 43(4): 269