References
- United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), Sources and Effects of Ionizing Radiation, Annex B Exposures from natural radiation sources, 2000.
- International Commission on Radiological Protection (ICRP), 1990 Recommendations of the International Commission on Radiological Protection, ICRP Publication 60, 1991.
- Civil Aviation Department, Cosmic Radiation, Flight Operations Notice 05/2002, 2002.