1. Butler D (2011) Radioactivity spreads in Japan. Nature 471:555–556
2. United Nations Scientific Committee on the Effects of Atomic Radiation (2013) UNSCEAR 2013 report: sources, effects and risk of ionizing radiation volume I. http://www.unscear.org/docs/reports/2013/14-06336_Report_2013_Annex_A_Ebook_website.pdf . Accessed 26 Mar 2015
3. Hosoda M, Tokonami S, Sorimachi A, Monzen S, Osanai M, Yamada M, Kashiwakura I, Akiba S (2011) The time variation of dose rate artificially increased by the Fukushima nuclear crisis. Sci Rep. doi: 10.1038/srep00087
4. Morino Y, Ohara T, Nishizawa M (2011) Atmospheric behavior, deposition, and budget of radioactive materials from the Fukushima Daiichi Nuclear Power Plant in March 2011. Geophys Res Lett. doi: 10.1029/2011GL048689
5. Nuclear Regulation Authority (2015) Monitoring information of environmental radioactivity level. http://radioactivity.nsr.go.jp/en/list/277/list-1.html . Accessed 2 Feb 2015