National Council on Radiation Protection and Measurements (2009) Ionizing Radiation Exposure of the United States. National Council on Radiation Protection Report No. 160, National Council on Radiation Protection and Measurement, Bethesda, MD.
 George, T., Rayan Babu, K.N. and Thomas, P.T. (2016) Reliability of Ultrasonography in the Diagnosis of Acute Appendicitis. International Surgery Journal, 3, 59-61.
 Berrington de Gonzalez, A. and Darby, S. (2004) Risk of Cancer from Diagnostic X-Rays: Estimates for the UK and 14 Other Countries. Lancet, 363, 345-351.
 Pierce, D.A. and Preston, D.L. (2000) Radiation-Related Cancer Risks at Low Doses among Atomic Bomb Survivors. Radiation Research, 154, 178-186.
 Preston, D.L., Pierce, D.A., Shimizu, Y., Ron, E. and Mabuchi, K. (2003) Dose Response and Temporal Patterns of Radiation-Associated Solid Cancer Risks. Health Physics, 85, 43-46.
 Sodickson, A., Baeyens, P.F., Andriole, K.P., Prevedello, L.M., Nawfel, R.D., Hanson, R. and Khorasani, R. (2009) Recurrent CT, Cumulative Radiation Exposure, and Associated Radiation—Induced Cancer Risks from CT of Adults. Radiology, 251, 175-184.
 Smith-Bindman, R., Lipson, J., Marcus, R. Kim, K., Mahesh, M., Gould, R., Berrington de Gonzalez, A. and Miglioretti, D.L. (2009) Radiation Dose Associated with Common Computed Tomography Examinations and the Associated Lifetime Attributable Risk of Cancer. Archives of Internal Medicine, 169, 2078-2086.
 Abdulkadir, M.K., Schandorf, C. and Hasford, F. (2016) Determination of Computed Tomography Diagnostic Reference Levels of North-Central Nigeria. The Pacific Journal of Science and Technology, 17, 341-349.
 European Commission (1999) Radiation Protection 109. Guidance on Diagnostic Reference Levels (DRLs) for Medical Exposures. Office for Official Publications of the European Communities, Luxembourg.
 Akpochafor, M.O., Omojola, A.D., Habeebu, M.Y., Ezike, J.C., Adeneye, S.O., Ekpo, M.E., Aweda, M.A., Opadele, A.E. and Orotoye, T.A. (2018) Computed Tomography Organ Dose Determination Using Impact Simulation Software: Our Findings in South-West Nigeria. Eurasian Journal of Medicine and Oncology, 2, 165-172.