Natural radioactivity in Appalachian fly ashes.
D000201:Activation Analysis; D000398:Air Pollution, Radioactive / Q000032:analysis*; D003031:Coal / Q000032:analysis*; D011883:Radium / Q000032:analysis; D013910:Thorium / Q000032:analysis; D014481:United States; D014501:Uranium / Q000032:analysis
D003031:Coal; D014501:Uranium; D013910:Thorium; D011883:Radium