U.S. Atomic Energy Commission. Health and Safety Laboratory. Carbon-14 Measurements in the Atmosphere - 1953 to 1964, report, April 1, 1965; (https://digital.library.unt.edu/ark:/67531/metadc13101/m1/1/: accessed April 16, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .