9[1]Pershagen G,Akerblom G,Axelson O,et al. Residential radon exposure and lung cancer in Sweden[J]. New Engl J Med,1994,330: 159-164.
10[2]Alavanja MC,Lubin JH,Mahaffey JA,et al. Residential radon exposure and risk of lung cancer in Missouri[J]. Am J Public Health,1999,89(7): 1 042-1 048.