Development of New Dielectric Systems to Provide a Minimum Volumetric Efficiency of Ten Joules Per Cubic Inch. Quarterly Progress Letter No. 2, May 8, 1968--August 8, 1968., report, January 1, 1968; (https://digital.library.unt.edu/ark:/67531/metadc1030778/m1/1/: accessed April 20, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .