1. Levels of radionuclides in plant samples collected around the uranium conversion facility following the criticality accident in Tokai-mura;Ban-nai;Journal of Environmental Radioactivity,2000
2. International Atomic Energy Agency (IAEA) (1999). Report on the preliminary fact-finding mission following the accident at the nuclear fuel processing facility in Tokai-mura, Japan. International Atomic Energy Agency, IAEA-TOAC, Vienna, Austria.
3. Science and Technology Agency (STA) (1999). Report of the Investigation Committee for the Criticality Accident at a Uranium Processing Plant (in Japanese), and also some related information from STA (including information in STA-Home Page (www.sta.go.jp)).
4. The composition of the continental crust;Wedepohl;Geochimica Cosmochimica Acta,1995
5. Terrestrial background radiation in Japan;Yamagata;Health Physics,1967