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3. Doses from radiocesium and 40K activities found in some tobacco leaves and cigarettes;Fletcher;Applied Radiative Isotopes,1994
4. 210Polonium entry into plants;Francis;Environmental Science and Technology,1968
5. Manolopoulou, M. (1990). A radioecological study of the coal power plant environment. Ph.D. Thesis. Aristotle University of Thessaloniki, Thessaloniki 54006, Greece, p. 178.