Green, P.H. & Hinton, L.W. Solid State Division progress report for period ending March 31, 1997, report, December 1, 1997; (https://digital.library.unt.edu/ark:/67531/metadc678485/m1/1/: accessed March 19, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .