“…The post-irradiation assay must be provided for each combination of matrix and trace elements. In many cases, Boyd, who published his war-time researches (20), and to the early USAEC program begun by Overman and Clark (111) (20,23,44,45,82,124,146,147,148,149) presented the basic principles of the method and the applications, in cluding experimental data.…”