Moore, R. B.; Lind, S. C.; Marden, J. W.; Bonardi, J. P.; Davis, C. W. & Conley, J. E. Analytical Methods for Certain Metals Including Cerium, Thorium, Molybdenum, Tungsten, Radium, Uranium, Vanadium, Titanium and Zirconium, report, 1923; (https://digital.library.unt.edu/ark:/67531/metadc12399/m1/1/: accessed March 22, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .