Bin Samat, Supian; Green, Stuart; Beddoe, Alun H. (1997). ”The 40K activity of one gram of potassium”. Physics in Medicine and Biology 42 (2): sid. 407. doi:10.1088/0031-9155/42/2/012.
Abd El-Aziz, N.; Khater, A.E.M.; Al-Sewaidan, H.A. (2005). ”Natural radioactivity contents in tobacco”. International Congress Series 1276: sid. 407–8. doi:10.1016/j.ics.2004.11.166.
U. S. Environmental Protection Agency (1999), Federal Guidance Report 13, page 16: "For example, the ingestion coefficient risk for 40K would not be appropriate for an application to ingestion of 40K in conjunction with an elevated intake of natural potassiumm. This is because the biokinetic model for potassium used in this document represents the relatively slow removal of potassium (biological half-time 30 days) that is estimated to occur for typical intakes of potassium, whereas an elevated intake of potassium would result in excretion of a nearly equal mass of natural potassium, and hence of 40K, over a short period."
