Cody DD, Kim HJ, Cagnon CH, Larke FJ, McNitt-Gray MM, Kruger RL, Flynn MJ, Seibert JA, Judy PF, Wu X. Normalized CT Dose Index of the CT Scanners Used in the National Lung Screening Trial, AJR Am J Roentgenol. 2010 Jun;194(6):1539-46.

http://www.ncbi.nlm.nih.gov/pubmed/20489094