Scheele, Randall D. & Casella, Andrew M. Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor, report, September 28, 2010; (https://digital.library.unt.edu/ark:/67531/metadc834359/m1/1/: accessed April 25, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .