324 (LCCN 2002-91021), which in turn cites Geigy Scientific Tables, Ciba-Geigy Limited, Basel, Switzerland, 1984. ↑ Environmental and Background Radiation, Health Physics Society. ↑ Internal Exposure from Radioactivity in Food and Beverages, U.S. Department of Energy (archived from the original on 2007-05-27). ↑ Brazil Nuts.