Gaylord, R F. Radioactivity of Potassium Solutions: A Comparison of Calculated Activity to Measured Activity from Gross Beta Counting and Gamma Spectroscopy, report, July 26, 2005; (https://digital.library.unt.edu/ark:/67531/metadc880321/m1/1/: accessed April 23, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .